Venu 2 vs Venu 2 plus simulator - display color differences

I'm developing a watchface, and something strange is going on. My guess is there's something wrong with the color format. The background is a .png file I'm loading as a bitmap
It looks as expected on the Venu 2 (simulator):

But it looks like something's off on the Venu 2 plus (at least in the simulator. I haven't been able to try it out on a physical device yet):

Am I doing something wrong, or is this simply a bug in the simulator?