Lightroom Classic: White balance doesn't copy correctly with preset and custom camera profile
Applying to a photo a preset that refers to a custom .dcp camera profile and then copying settings from that photo to a virtual copy produces incorrect results on the copy, and the Library thumbnails fail to update. Tested on LR 10.1 / Mac OS 10.15.7. Original report:
This misbehavior is different from the LR 10.0 bug fixed in 10.1:
1. Import the camera profile Canon EOS 5D Mark IV Kodak Portra 400 UC C.dcp and the preset C - Kodak Portra 400 UC.xmp from here:
2. Download and import the sample Canon EOS 5D Mark IV raw from here, with the option Build Previews: Standard:
3. Create a virtual copy.
4. Take the original into Develop and apply the preset C - Kodak Portra 400 UC. Note that its Temp/Tint changes from 5050 / +5 to 5500 / -21.
5. Do Settings > Copy Settings, click Check All, then Copy. Move to the virtual copy and do Settings > Paste Settings. Note that the virtual copy's visual white balance changes but Temp/Tint remains at 5050 / +5. The original and virtual copy look different in Develop:
6. Change the WB of the virtual copy to Auto and then to As Shot. It now has Temp/Tint of 5050 / -21 (same as the original), and flipping between the original and the copy while remaining in Develop, the two images are identical.
7. Go to Library Grid view and observe that the two thumbnails still look different:
8. Select both thumbnails and do Library > Previews > Build 1:1 Previews. The two thumbnails now look the same.