I have never had a single issue with Amazon Payments but today I sent funds from my wife to myself (different bank accounts) and it didn't go through instantly like it usually does.

Odd thing is the transaction doesn't show up in my activity at all (not pending, simply nothing). I thought maybe I didn't hit send or confirm at the end but when I tried to send the funds again, it said I had sent too much for this month already (meaning it must have gone through).

Hope it's just a fluke.