It's was a very minor event but left me 
A long-time friend (A; 8yo) of DS1 and DS2 was booked to come over to play/sleep over - we have developed this reciprocal thing with the parents over the past 6mo or so. I get on well with the parents - hanging out at their house chatting during playdates sort of thing. We've known them for nearly 10 years.
So the doorbell rang and I went to answer. A was there, plus a woman I didn't know. She introduced herself politely and handed over the friend's clothes/sleepover stuff, then said she or one of the parents would collect tomorrow at the prearranged time (slightly earlier than usual as my family have a prior engagement). She then headed off.
I was a bit bemused, tbh; if A's mum had texted to say 'Just sending the boy over with 'named friend' now; thanks, see you tomorrow!' then it wouldn't have felt weird at all. But she didn't, and it did/does. We had another couple of friends here at the time (they had randomly dropped in plus toddler) and they seemed to find it odd too. I can't quite articulate why though!
Please either explain it to me or tell me to give my head a wobble
I repeat, this is not a life-changing incident. Just.... odd.