A warning right from the off - this post may be considered a bit controversial and possibly a bit of a rant, but I'm hoping you'll stick with me as I discuss this topic. My points here come from personal experiences, having changed role at the beginning of 2020. Despite speaking from personal experiences, this problem isn't unique to me or my employers so feel free to put yourself in my shoes.
So, what was I and what did I become? (Sounds very philosophical!) My previous role was as a network & security engineer (N&SE) and I moved to being a deputy senior information security officer (Deputy SISO) during the previous restructure. It's also worth knowing that while my background is in Microsoft systems and support, I'm also versed in Linux. Indeed, with the exception of my Chromebook all my home computers are Linux based. (The rest of my family uses Windows.)
As part of my old role I was (jointly) responsible for maintaining switches, routers, firewalls, servers (to an extent, although there was a server team for most server work) and Linux installations. My N&SE role also involved configuring and maintaining the certificate authorities, DNS and Active Directory Group Policies along with our two factor authentication systems. Those that read my blog regularly have probably noticed I turn my hand to a lot of things, also being a developer outside of my main day-job so it's fair to say I had my fingers in many pies.
During the restructure the N&SE and Server Support roles got merged into Infrastructure Engineers. I want to make it clear there's nothing wrong with that job - I just didn't want to do it. I'm increasingly focusing my career on cyber security / infosecurity and I've previously been responsible for servers, SANs etc so I knew I wasn't interested in being an Infrastructure Engineer. In the event I'd not got a full time security post I'd have accepted the infrastructure role but I don't know how long I'd have remained.
Where I work, the Deputy SISO role is more governance than actually implementing technologies - I joke with the other Deputy SISO that "we don't do anything". For the most part, I look at logging, keep abreast of security related developments, (jointly) run the vulnerability management programme, handle security incidents and give advice. My role, on paper at least, doesn't include much of my old N&SE workload.
Caveat: I've simplified those roles but hopefully you get an idea.
On moving roles in January 2020 I left a vacancy in my old team. I was also taking a lot of knowledge with me, despite writing a lot of documentation. Experience counts for a lot, especially when I built "the thing" so I fully expected there to be some months where I still did a bit of work for my old team, at least until my replacement was up to speed. I also expected to run some knowledge transfer sessions and those have gone really well.
I remember in February 2020 I was asked "how does it feel to have left support?", as my new role doesn't particularly focus on user support. My reply was that I hadn't had the opportunity to find out yet, although that was OK because I still expected to be dual wielding.
What's happened since?
Unless you've been hiding under a rock, wise given what happened next (!), you'll know the Coronavirus pandemic hit. Undoubtedly that will have impacted the changes within my organisation by holding up training and similar. Nonetheless, I've not been fully released from my old role. I've also had to take on roles that I never did and aren't part of my current job - migrating web applications from unsupported servers for example. Here we are in 2021 and it's possible I'll end up implementing some changes on the Certificate Authorities which is not part of my current role.
You're a team player, so what's the problem?
I'll be the first to admit that the problem can depend on my mood, and that I fully intend to keep a bit of a hand in on the implementation side. I feel it's important to be able to talk to other teams about the things I'm asking them to do whilst understanding how that might be done and the implications of such changes. Further, if there's an outage or someone asks for help I'm more than prepared to get involved (even if that's just making the tea!).
So, what's the problem?
The problem is that unless I'm fully released from my old role, other people don't have opportunities to learn in the same way. If it's a case of "it's OK we'll ask Jonathan to do it" I become a single point of failure, or a bottleneck. People need to learn to do the job they're in, developing their skills and increasing their experience. Sadly, there's still things from my old role that I'm being asked to do because I built the solution originally - fair enough if there was no documentation, but you've probably guessed by now that I write things down!
Another problem is that the organisation develops a false picture of capability. Each time there's a problem from my old role that I solve, perhaps because only I can solve it quickly, the organisation doesn't see one man, doing someone else's job - it sees "my problem was fixed, great, we obviously have a team that can do that". That's a huge problem in terms of resilience.
(By the way, the same is true if you continually work extra hours but don't bill your organisation / clients for the extra work. You create a false picture and requests for more staff will then be met with "but you've got capacity, clearly". Don't work extra hours for free folks!)
What's the solution?
Sadly the best option is not a quick solution - lots of training and hand-over sessions or providing help after someone else has already tried (or just needs a sounding board). Note though that it shouldn't be my job, in this case, to teach someone everything about their role or the technologies they use - they have a duty to undertake some training of their own but it is reasonable to help out.
An alternative approach is cut throat - "Jonathan won't be doing X any more". I don't advocate that approach and I feel it does more harm than good.
A plea to bosses
If you're a manager that's had someone move into your team from elsewhere in the organisation, please rather than saying "we'll end up doing that" (where "we" means "my new hire") say "it'd be great if you could give them a hand and be available for questions". As a general rule, if someone asks for my help I'm willing to give it. What I'm not willing to do is someone else's job for them because that's unfair.
Also, if you're the ex-boss asking your ex-subordinate to do the work please don't be doing that because you know / think no-one in your team knows how. Set up some sessions between your ex-subordinate and current team to get that knowledge transferred, or tell your team to learn how to do something. Please don't hide a problem (your problem) by getting your ex-subordinate to do the work.
What's the impact on me?
Starting with the obvious: if I'm doing part of my old job I'm not spending that time on my actual job. That potentially means losing days working on my actual projects that I'll have to catch up.
On a more personal level, the worst thing is having to assist with the same thing multiple times. This gets me down. I also recently concluded a project "because I'd started it" and the other team didn't have capacity to take it on, all the while I was being moaned at by one of that team because the system wasn't good or how they would do it. Some of the comments were fair (and already being addressed) but if you're going to make a lot of noise about it either pitch in or pipe down. That project has been handed over now and it's a weight off my mind. Due to the complainer, the amount of hand-over I did was reduced, because I wasn't prepared to deal with them or the system any longer. Instead I wrote some documentation and pointed to the vendor's guides.
Do I move to saying "not my job" too quickly?
It's been suggested I'm too quick to say "that's not my job" or that it's my default position. I like clearly defined boundaries, and grey areas and I really don't get on so I try to be objective, looking at the request and determining if that's really a job for my role or not. Given everything I've said above, it might be I'm saying "not my job" because a) it really isn't or b) I've been burnt helping out before, but if it actually is my job I'm not one for shirking the work.
Will I pitch in anyway?
Ultimately if my boss gives me a lawful direct instruction I'll do the work, so if I'm ordered to do my old job I will do so. That doesn't mean I'll do it without protest, and I'll likely highlight to them the need for the other team to get some training. I'm also a firm believer in Abigail's Oath, which is how I'll conclude this post:
I am hired because I know what I am doing, not because I will do whatever I am told is a good idea. This might cost me bonuses, raises, promotions, and may even label me as "undesirable" by places I don’t want to work at anyway, but I don’t care. I will not compromise my own principles and judgement without putting up a fight. Of course, I won’t always win, and I will sometimes be forced to do things I don’t agree with, but if I am my objections will be known, and if I am shown to be right and problems later develop, I will shout "I told you so!" repeatedly, laugh hysterically, and do a small dance or jig as appropriate to my heritage.
 For those not familiar with the idiom, "fingers in many pies" means "involved with a lot of things".
 SAN - Storage Area Network, like a big storage array.