Sponges resetting to dry and Arrows multiplying and falling down

Note: Both bugs occurred in creative mode on the same 'old' map

 

Bug 1: I placed some Sponges, all of them drained the nearby water like they're supposed to, but some of them always re-set to 'dry' status before the water can flow back to them so I got a loop.

 

Bug 2: I fully enchanted a Bow (Flame, too) and shot it at a stack of placed TNT (I had no Arrows in my inventory). Sometimes, I heard multiplying arrow hit noises and all TNT downwards from the one I shot at got ignited.