why is my anemone shrimp destorying my BTA?

[marlboro man]

ever since I added an anemone shrimp I have been noticing cut off tentacles of my RBTA lying on the sand bed every few days.

I suspect the shrimp is doing the damages as he is hosting in that RBTA.
I thought they are supposed to be symbiotic, but why would the shrimp cut off the tentacles?

should I remove the shrimp? or is this a natural process?

thanks