AIBU to raise concerns about a colleague doing far less work?

This! You’ll only make yourself look petty commenting on someone else’s workload when change won’t affect you. Use it as an example why you should be paid more for your extra workload.

we had one of these at my work. There was a long term plan (a year plus) to manage them out in a legal and gentle way. It was of course very confidential and noone would have known about it. But don't be so sure it is being ignored.

There’s always a possibility that theres factors you don’t know about. Speaking up may make you seem silly ig she actually has a reduced hours contract but spreads for health reasons, something you may not be privy to

But is she just much more efficient at her work?

Are you sure she doesn’t work from home or have less hours for a reason? And how can she always be on holidays- do you take all your holidays or is it that she uses hers and nobody does? Just asking because I’m one of my old jobs me and another girl got in an hour before everyone else so left an hour earlier (we were all on flexi), and we regularly got comments on how lucky we were to get to leave early or would be asked were we going to stay on time today if working late. Maybe she gets her work done differently to yours

If it has no effect on you and the management are not concerned, then why would you do anything?

So what's the solution?

Why not drop back to working at the same rate as your colleague and let the work pile up. When your manager complains you point out that you are working at the same average speed as your contemporaries. If your organisation is unionised the manager will not like to get into an argument about that.

Rather than complaining and sounding petty, why not ask for a pay rise, justifying it as being to reflect the workload you have in comparison to others who have the same salary and role as you, but much smaller workloads.

One word of warning, as a manger I tend to know a lot more about my team than individual team members know about each other. I'd tread very carefully OP else you will not show yourself in a collegial light. Could backfire.

We have one of these at my work as well. Management have said the only way to fire someone seems to be if they kill someone. So it is what it is!

Mhm, doesn't sound fair. Is your colleague working full time, same as you? Saying something sounds very petty though.

If mentioning it won't change your own workload then I honestly don't see what it will achieve. The issue is not with the colleague, it's with the organisation who knows what's going on and are happy for it to continue.
I am unahppy about how some of my colleagues handle their sick leave, for example. If I take a day off sick, I always check my diary and send an email to admins explaining where to move my face to face contacts. So I am keeping my workload with myself. Nobody else does that and I am getting weekly requests to pick up extra contact "due to staff sickness". But I am not going to kick a fuss about that either because it isn't going to make any difference to how I do things and my personal feelings are irrelevant because they are not doing anything outside of what the organisation expects.