Confirmed Harvest has a chance of restoring a used berry at the end of the turn. If conditions for berry use are met the berry will be immediately used, however, and not be restored again. Does not restore Berry Juice. Will always activate in sunlight. If a Pokemon uses its berry, does not regain the berry from Harvest, switches out, and then switches back in, the game still 'remembers' that the Pokemon had that berry and can regenerate it by Harvest, can regenerate its berry back on the switch(mien, CyzirVisheen, #2, #3, sb879, Pidge)
Umm... I just tested this myself and it is partially incorrect. The berry will continue to be restored indefinitely, in or out of sunlight; however, on the turn it activates twice, Harvest does not return the berry a second time, but it will the following turn after that, continuing to activate as soon as it is recovered, until the berry cannot activate anymore (e.g., tried it with a Leichi berry, and it kept getting eaten until exeggute's attack was +6)
I do not have a way of recording a wild battle on my DS, but I will work on recording a vid of this in the battle subway and then posting the video number here.
EDIT: Here it is: 66-52221-90606
Sure makes Harvest a hell of a lot more interesting now, doesn't it? :D