Pink boundary around objects in my game

Hi everyone,

I purchased early-access Gnomoria on steam after seeing my friend play for a few minutes. I love the game but after jamming on it for a few days I've come to realize there is a bizarre graphics bug occuring. All my items and gnomes have a pink boundary showing. This is in Windows 8.1 on VMFusion Pro 5.03

Here is a link to a screenshot: http://imgur.com/fPoU9Pf

This isn't occurring in any of my other sprite based games I play this way, can anyone tell me what might be causing this? The pink border is the color of the transparency color on the pixel art sheets for the game.

Thanks!