Maybe MCPE-44178 has little relationship to this.That just like a render error.
I guess you can't reproduce it because some growsteps use the same texture.According to wiki,I think the issue is at the step of 7
no addon,no mod,just pure map
In my opinion,this issue takes place because of wither location movement AI,movement is OK but view also following is unomal,so a binding of movement and view is a error
Maybe MCPE-157761 has little relationship to this.That relates to move AI but this about spin AI.Besides,a freeze should make a stable eyes line instead of spinning.
it still a issue in my test of 1.21.1,maybe your test time too short to reproduce.(about a few minutes)
it is my old resource pack.
sorry🙏
video has upload