I know what you mean there.
I am wondering if you might have double-clicked the send button when you sent the acorns, sending the request twice. The first request would have gone fine but the second one found insufficient acorns. It's the only guess I can come up with. Do you know if you clicked once or double-clicked on the button?
Either way, I should try to find a way to not do it twice if you click twice. That would be a problem.