Mine comes off if grass is built up under that green pivot or the bolts when I back it off the trailer. It's a real beeach to get back on too.
Tire psi may be a factor under normal circumstances like what was posted.
Also, when you get the plate make sure everything is lined up good.
Those plates take abuse from bumping into stuff on turns and such.
Remembering all my departed friends.
Well, I hope everyone is happy now.