Offset not mirroring properly in animationplayer 2d

[gaunt turret]

I have an animationplayer where I animate the offset for my player sprite. There is one frame of my run animation where my sprite was off so I had to offset it by -9x. It looks fine running to the right but the offset looks very wrong when running to the left. What should I do to make it look identical when flipped?

[pine prawn]

generally you should setup your sprite sheet in a way where all frames need the same offset.
but alternatively, fliping the sprite using a negative scale on one axis should also flip the offset with it.