Ano vs Rex hitbox issue

I noticed that Rex can apply full bonebreak to Ano when it bites very closely to tail, but Rex's jaw doesn't touch it. There must be something wrong with hitbox because it happens on every single community and officials server. I tried to test it when I was standing still and hitbox seems to be normal, it happens only when I'm moving. Even if Rex touches tail slighty, it's not close enough to base body to trigger full bonebreak. My ping & connection to the server is fine, so I don't think that's the case since other Ano player I know also experiences it. You can see how it looks like on my video.

Rex can apply full bonebreak to Ano if it hits closely to it's tail or tip of it.

Rex shouldn't be able to apply full bonebreak to Ano if it hits closely to it's tail or tip of it. It should deal damage, not full bonebreak.