There's a Polymer related bug that no one has reported yet, and I think was recently introduced (I'm not sure how recently, but I started noticing it a few weeks ago...I didn't realize what it was back then and didn't report it).
There is a problem with floor aligned and wall aligned sprites not being displayed with the correct game palette when the game palette changes (e.g. when nightvision goggles are used). I have only seen this happen in WGR2, which has a modified nightvision palette.
-Many wall aligned sprites continue to look normal when the goggles are on, instead of having the altered palette.
-Some floor aligned sprites do have the altered palette when the goggles are on, but then they continue to have it even after the goggles are off.
-In one instance which I haven't been able to replicate, all of the wall aligned wood planks in the map (even those miles away from where the goggles were used) continued to be displayed with the altered palette after the goggles were turned off. Turning goggles on/off again did not fix it. I have a screenshot of this attached.
EDIT: The easiest way to see an example of the bug is to kill some enemies with the rocket launcher while using nightvision ("spirit vision" in WGR2). When you turn them off, some or all of the blood pools will still have the goggle palette.