I have encountered a few things that could possibly be bugs.
1 - For the past few versions of ZC whenever an arrow hits a "block all" combo, the "arrow hits" animation gets stuck wherever the arrow hit and you can't shoot another arrow until you leave the screen.
2 - I am using a scripted item and the item cost never drains when I use the item.
3 - I am using the boomerang with a custom sfx attached and if I use the boomerang and leave the screen before it comes back to me, the sfx plays continuously until I throw it again. Could this be because of the length of the sfx?
4 - Starting a few ZC versions ago, FFCs in my quest started misbehaving and some just don't appear at all. They worked fine and after I upgraded to a new version (I can't remember exactly which version it was but it was a couple of months ago) they are broken.