visual error when hitting a mob after using an egg with the another hand

when I hit a sheep after it has been spawned, the full damage bar appears but almost does not lose life on hit

What I expected to happen was...:
the sheep die

What actually happened was...:
the sheep don't die

Steps to Reproduce: u need a weapon who insta-kill a sheep and a sheep egg on another hand
1. generates the sheep
2. hit the sheep

if all goes well (like the video I uploaded) you should see a full damage bar to kill the sheep and the sheep don't die

I use translate, I don't speak English