I have two rasters that have been cropped and masked. One with a colortable (test_ctb.tif), the other without (test_nctb.tif). For the NoData pixels, the one with colortable (test_ctb.tif) identifies its value as 0 while it should show NoData. When I switch to unique values, then both rasters show correctly NoData for that pixel. The color table works fine in ArcMap 10.8.2 though!

