Patience, Snipe, patience... Phosphorous levels are dynamic, so your snapshot in time, was only that, the phosphorous level when tested. The addition of lime unlocks phosphorous that wasn't previously available to the FA. It's a common agricultural practice.
Give it time and your pH will return to normal levels. 8.3 isn't anything to fret about. However, you should remove FA, dead or alive, and take it easy on the feeding, just to be safe.
