On several occasions now I have been in creative mode and unable to cancel creative flight due to a block being against my head... it doesn't always happen and I don't know what induces it either, you may need to die in survival first or maybe it's related to that crouch bug I have no idea.

This isn't that important but it's strange and frustrating. 

I would link a video but all you would see is just me flying around the ceiling for a while before dropping down slightly in order to cancel my flight