Odd texture bug with Mooshroom's Mushrooms

the mooshroom have this weird texture glitch on the mushrooms on their backs. The glitch looks like the texture "Spikes" upward if you look at the mooshroom just right.

I made a short 30 second video and uploaded to youtube of it exactly with my f3 on https://youtu.be/Kgqj8b8QhwQ