Wall requests disappearing...

I cleaned up my wall box yesterday...deleting messages older than 2 weeks. Now I have discovered that I only have wall requests up to 9 hours old, that will stay on my wall. The name will stay if it is more than 9 hours, but what they were requesting is gone. I noticed this as I am doing the gold heart quest. I don't gift any of them until I am done collecting 30 of them and exchange with the Cupid. Then I was going back to my wall and gifting any that were there. Before the cleanup, I might have them for a day before I would gift them. Has anyone else noticed this happening to them? How long are the requests staying on your walls???