Currently, the EXR reader only considers uppercase RGBA channel names in single-layer EXRs, which leaves out the lower case rgba channel names we started using for data and vector passes in Cycles and the compositor. Further, a single V channel was also ignored, which is by convention used for BW passes. This patch extends the single-layer channel recognition methods to include lowercase rgba and V channels. Pull Request: https://projects.blender.org/blender/blender/pulls/114339