Well, a few days ago I traded at 7:15PM EST.
The next day I tried to gift again at 6:45PM EST, because some folks thought it was down to every 22 hours. It would not let me gift it.
Someone else said it rests at 7:00PM EST, so I waited 15 minutes and tried sending again at 7:03PM EST and that time it went through.
So, it didn't take 24 hours, but it was almost there.
I don't know if the 7:00PM EST time reset is true, or if it just happened to work for me because I was already in that time area.
I have traded every day a few minutes after 7:00PM EST since then.
I will give a try tomorrow after 7:00AM and see if it goes through, and report back.