(2.2.12 alpha) Regression; Various midtextures display broken colors.

After the big flurry of commits, I decided to test the latest build of 2.2.12 alpha. What I noticed is that a lot of midtextures are now displaying broken colors (but not all of them). The following attachment shows an extremely simple test map showcasing a broken midtexture (from the Castle Eggman set). MAP01.wad

An example shot, the interesting thing is that the glitch palette changes every time the game is started.