Hello there! I checked and both Lizardfolk animations seem to be centered. The difference is that "Idle" frame size is 16x24 while "Attack" frame size is 48x56, so you have to take that into account when changing animations. I did it this way since the attack animations need a lot more space than the normal Idle and Walk animations, so I wanted to save some file space.
If this doesn't work properly in your game engine, maybe you can try making all animations the same size (in this case, 48x56 or whatever frame size you prefer), and rearrange the sprites with that grid in mind. That should work.
Sorry for the inconvenience! If you need anything else, let me know.