Yesterday I requested all neighbours for an oven part. I have over 100 relatively active neighbours so I wasn't expecting to be waiting too long, but even hours after I'd sent it I still hadn't received anything.
I checked on my phone's account (main game is on iPad, second game is on my phone, both accounts are neighbours) and the request had not gone through to that account.
I went on today though and it's like as soon as my gifts weren't maxed, I started getting the materials I requested. It's really annoying because I'm trying to complete (I'm a bit late) a goal thing and I don't want to have to wait until tomorrow