Unexpected blender result

[cinematik]

There seems to be something wrong with the file, that the blender started to give some unexpectedly dark trace. I've tried changing the canvas settings and resetting the blender settings. Just one layer in the file. What could it be?

102423

[cinematik]

Even the default brush on the base canvas gives weird results in a new file.

102424

[cinematik]

as it turned out the reason was in color picker where `metallic` value was not zero

it would be better to completely hide that controll but it seems there is not such an option