Hostile mobs 'shake' their heads when they can see the player but can't reach it

In 1.21.6 and earlier(even 1.15), hostile mobs when chase the player and cannot exit in a stuck area, keeps looking at the player and at the same time wants to look somewhere. It doesn't sound natural and it looks weird.

Steps to Reproduce:

1. Put hostile mob in an area that cannot leave, preferably a straight line.

2. Stay at a distance of two or three blocks in a diagonal angle and one or two blocks above from the area’s edge for more perception.

Expected Result:

Hostile mobs focused to look only to the target player OR only look somewhere.

Actual Result:

Hostile mobs are undecided to look at the target player and look somewhere.