GIMP 2.10 LCh Chroma blend artifacts - vertical stripes
Sometimes in addition to producing wrong results ( #2933 ), also there are artifacts somewhat randomly appearing, "randomly" meaning I haven't yet figured out how to reliable produce the artifacts.
Making the invisible Normal layer in the above XCF file visible, and changing the blend mode to LCh Chroma, changes the placement of the artifacts:
Creating a new image just the same as the previous image, but this time using perceptual precision, produces new colors and a new pattern of artifacts:
newly-created-same-colors-but-perceptual-precision.xcf
Adding an alpha channel sometimes makes the artifacts disappear and sometimes just rearranges them. If, in a new image, there aren't any artifacts from one Chroma layer over gray, try duplicating the Chroma layer.
Resizing the canvas at sometimes? always? makes the artifacts disappear, and undoing brings them back, but in a different location. Perhaps the size/shape matters. My test image is 450px by 450px. But I created a 900px by 900px image and wasn't able to produce artifacts (limited testing).
Running Curves on the Background layer can add, change, sometimes remove the artifacts, and of course also can change the hue of the resulting blend ( #2933 ).
Edit: So far I haven't been able to reproduce this using GIMP-2.99. Testing for 2.99 and 2.10 done on Debian Sid using babl/GEGL/GIMP updated yesterday.