mobile

Hello. Noticed that my phone when switching between color / black image (for more than 50% of the screen) to the predominantly white image brightness increases slightly. Not much, but noticeable. For example, watching videos, and because of the change of the composition changes brightness. Another example: I sit reading twitter, I go to a tweet - brightness falls, go back - rises.
And it's all sharp and quite a bit. Not sure, but it's only for android 5+, ie on OxygenOS and CM12.1unofficial. Pierced archive bacon_firmware_update_2015_02_26.zip before flashing android 5+, as to produce an error. Tell me, what do I do? If you want, I can put 11S to check whether the problem is on it. Thank.
P.S. Mention of this problem on the forums is not found.
During firmware CM12.1 there is a line "skipping MD5 file: not found".
Automatic brightness adjustment, Reduce power consumption and Enchance colors disabled.
But I have the impression that Enchance colors as active.