WowAce

This is happening in the classic version.

Title pretty much sums it up.

When you set up a frame with horizontal mirroring, whenever the unit GAINS health/mana, the background behaves strangely, whenever they LOSE health/mana, the background is as it should be.

It looks kinda like the background is being squished so that the lighter part of my bar texture is showing up in the small space of the health or mana defecit. It appears slightly lighter than it should. You can notice it best if you have your target frame set up to be a mirror of your player frame and cast a spell.

I'm also using the BantoBar texture which makes the issue a lot more obvious than some of the other bar textures, but the other textures do exhibit the same issue.