I might have found a bug in the new AMD driver 19.12.2 regarding the setting called "Custom color". When the setting is "off", it equals to overwriting color temperatur to 6500k.
This must be a bug, because setting "Custom color" to "on" and turning off "color temperatur control" will equal to "auto" (non-custom color temperatur) setting. I think they made a mistake there.
Setting "custom color" to off should set "color temperature control" to off as well.