When your FOV changes (e.g. sprinting or using a swiftness/slowness potion) while wearing a pumpkin, the pumpkin overlay zooms in and out. This is extremely distracting and does not occur in Java Edition.
The following is a gif of this behavior:
https://media.giphy.com/media/1n3MZClxsfYs05rMZG/giphy.gif
Affects 1.16.100
Affects 1.16.200.56 Beta