No it’s not. Same behaviour with 2.8/unfortunately.
It seems it may be linked to LiveDisplay feature but I haven’t find a way to fix this problem which is not very important but really boring. Colours are bright, I switch off the screen, turn it on, colours are pale. I wait few hours, switch on the screen, colours are bright.
I performed two screenshots, one while the screen is bright, another while it’s pale (10 seconds away from one another) and sent them to another device to check: they are exactly the same. So the problem is definitively linked to the way the screen physically displays what the OS generates, probably affected by a feature telling the screen how to display it (e.g. LiveDisplay).
I don’t really want to downgrade actually. I’d rather like this issue to be fixed. If it does appear this is an OS issue.
@urs_lesse yes I realize that forcing the brightness to maximum fixes the problem.
Actually something has changed between 2.6 and 2.7 because before 2.7, the decrease of the brightness did not lead to such modification of the colours. It’s very hard to explain but now when the brightness decreases, colours are… less warm I’d say.