Wither skeletons are stuck on wool when you trick them there or spawn them there with a spawn egg

Wither skeletons are stuck on wool when you trick them there or spawn them there with a spawn egg or summon them there. Here i will show you a picture and you will see that i am on survival but it dont chase me because it’s on wool. I am also going to show you a video and you will see that it only chases me when I step on the wool.