Possibly being too sensitive about this...
I've recently returned after maternity leave and I am doing a 4 day week. This was happily agreed by the (large) firm and by my department's manager. I suspect my small department is unhappy about it though. We were busy even before I went on maternity leave and there had been a hope that the department could keep my maternity cover and my p/t hours would become the 'extra' member of staff we needed (my manager didn't probe for details before I went on mat leave but as it was DC2 there was a sort of understanding that I was unlikely to come back full time straight away).
I get that this causes staffing issues for the department and I'm really sympathetic. As it is I'm starting to understand why people say that 4 days a week is just 5 days a week on less pay
I try my best to help, I often work during my commute, keep an eye on my emails on my non-working day, and don't really take much of a lunch break.
However my direct colleagues often make comments about how busy they are (very true) and say things like, "of course, it's even worse on X [the day I don't work] day". Our workload is hard to plan as we respond to requests coming in, which doesn't help. Because of how we work, most work related emails are cc'd to the whole department. Every time I read my emails after my non-working day, it's full of comments to our clients that we might not be able to hit their deadline because the department is "short staffed today".
It's starting to annoy me now. Which is where I am probably being U. I know they are technically short staffed but... they did agree to this working pattern, it's a very common working pattern in the firm as a whole, we just haven't had someone do it in this department - I'm the only parent in the whole team. So after 2 months its just starting to feel like a bit of a dig at me. It's not like I've had a last minute annual leave day or anything, I will never be working that day. AIBU and oversensitive about it?