Axolotl don't have a animation when attacked by the looks of it in the video shown, this would have probably been T pose if this bug affected mobs like zombie or Pillagers.
MCPE-131322
Axolotl don't animate properly when attacked on the ground
Resolved
Fixed
4
(Unassigned)
625411
Confirmed
Multiple
Windows 10 64 bit
1.17.10.22 Beta, 1.17.0
1.18.0.20 Beta, 1.18.0
Retrieved
Ignore that the hand position looks fixed, I forgot to turn of a texture pack I was using but I can confidently confirm this bug is very much in the game.