I consider this to be a pretty important bug especially for survival players since it can cause you to fall to your death if high enough. I haven’t been able to trigger it 100% of the time.
How to reproduce: ride off the happy ghast while holding down the go forward key.
What happens: you won’t be able to move for a split second before clipping off the ghast, sometimes the running camera effect appears before falling.
I have attached two videos of the bug, one in first person and another in third person.
I checked and it works. I think it's worth fixing this bug soon, as it significantly hinders the gameplay, especially when you're surviving.