To think this is odd for the nursery to have asked?

[Nnjlw]

We went on holiday at the start of June and I forgot to tell the nursery on the Friday (we went on the following Monday). I did mention it to the staff in the room (DD is 2.5) but it obviously wasn’t passed on the reception. They rang in the afternoon of the Monday to ask if everything was ok as it was unusual for us not to be in (DD is usually in mon to Thurs and sometimes Fri) I explained we were on holiday and they said ok have a nice time. I’ve felt really weird about it since it happened as it was like they were checking up on me?! She’s not at school so we don’t have to take her in yet. Am I being a bit paranoid here? Would your nursery do this? Is it normal?

Safeguarding. There's been loads of cases, mainly in the US, where the parent has on autopilot driven to work and left the child in the car (if for example it wasn't their day for drop off so they forgot they had the child) and the child was left in the car and died. If nursery had got hold of those parents it may have saved the child.

Just basic safeguarding.
Staffing and lunches come second to that. I'm almost surprised it was so late before you got the call. I'd expect the call before 10am the same as schools.

There was a case of a boy dropped off 100yards from school he was abducted and murdered before the alarm was raised at 3pm when his grandpa went to collect him.

As others have said it's mainly for safeguarding reasons, but also if your child is unwell they like to know why in case it's anything contagious. Sickness bugs/impetigo/hand foot and mouth/chicken pox... the list goes on. If your child had anything like that they sometimes send letters home with other parents to make aware of something going round.

It really doesn't matter how many times you mention that you told staff in the room that your daughter wouldn't be in. Nobody will pay any attention to that part, you'll just have a thread full of people saying safeguarding.