12 hours into the "final" render of an animation sequence I noticed that a texture map was not rendering properly compared to draft renders of the same animation. It turned out the problem was that I had Auto-convert textures to TX activated for the earlier draft renders, but I'd deactivated it for this final render (I didn't want it to run that conversion for Every. Single. Frame.). I was under the impression that since that PNG had the (tx) next to it in the Asset/TX Manager that Arnold would be using the .tx version in this final render, regardless of whether Auto-convert was active. I guess I'm not understanding how that really works, and the online manual isn't helping me much.
In this case the texture is a white on black PNG of traces on a circuit board that I'm running through a color correction node (to tweak the gamma) and then into the cutout opacity of the geometry of a light grey plane floating just on top of the PCB model (shadows deactivated).
Without Auto-convert activated the traces are barely visible, as if the gamma is being crushed, clipping out almost all of the white.