Description: In GIMP, painbrushes, airbrushes and pencils don't work on images when color correction is on. They simply don't paint anything. However, the issue is even more complicated than this:

TIFF 16/32bit files, having other than Gimp's native sRGB do non't
have working painbrushes while color correction is on.

JPG files converted to 16/32bit while having RTv4_sRGB profile do
non't have working painbrushes while color correction is on.

TIFF files having 16b/32bit floating point WORK.

TIFF 16/32bit files having converted profiles to GIMP's sRGB WORK.

TIFF 8bit files WORK

JPG 8bit files WORK.

Reverting back to lcms2 2.9 and all is normal

Additional info:
* GIMP 2.10.18 and LCMS 2.10
Reported to GIMP devs and emailed to lcms2 dev:
https://gitlab.gnome.org/GNOME/gimp/-/issues/5192

Steps to reproduce:
You need to use color profiled display and have color management enabled in GIMP.

The easiest way to reproduce this is to export a file from RawTherapee.

- Export RAW directly from RT to GIMP using 16bit integer, RTv4_sRGB color profile
- Notice that brushes (pencil, airbrush, paintbrush) don't paint anything.

- Reverting to lcms2 v2.9 makes everything ok. This is the 2nd issue I reported about lcms 2.10 in past few days. First was seg-faulting GIMP with dev fixing it and now this. I'm not sure lcms 2.10 is stable to be used, but that's just my opinion.