Wither Skeletons Can´t walk in 2,5 Block high spaces

Wither Skeletons aren´t able to walk in two and a half block high spaces despite their hitbox being 2.4 blocks. They will stand in one place and when given a Target such as a iron golem or a player the will try to walk, which is visually represented by them lifting their sword, but they only lift it partially. After it will return to it´s original position in a very glitching motion