This already got fixed for everyone where this bug occurred. Please join the support discord next time when you encounter any bugs (not only with my packs)
The pack is very impressive as it adds a whole new dimension to minecraft mobs. However, one problem is that the animation could be smoother since mobs will move a little funky
This isn't an error of my mobs. You've to optimize the plugin configuration of ModelEngine and the armor stand performance on your server for the animations to be more smooth.