Creepers do not defuse when switching from Survival to Creative/Spectator

The bug

So whenever I go into creative mode and there is a creeper nearby it explodes. I was just testing an automated music disc farm, and when I went back into creative mode to get my stuff the creepers that weren't killed exploded for some reason. I am very confused right now..... ._.

Code analysis

Code analyses can be found in this comment by Xander Smith and this comment by BillyGalbreath.