I have a MacBook Pro Touch 2017. A few days ago, I noticed that the display seems to have started to have a very faint warm/reddish tint, but I can tell the difference nonetheless. The greys aren't "cool grey" anymore, but more like "red grey", and the whites are sort of "faint pink-white".
I really started noticing this because once after startup of macOS, the display was first "cool/bright" (what I would describe as normal), but perhaps 30 seconds after entry to the OS/Desktop, the whole screen switched to the red tint. This "alteration" doesn't happen every time starting the computer, but quite regularly. When comparing the display to that of a MacBook Pro 2013, it is clearly bluer/cooler in its display.
Note that the displays aren't calibrated beyond the factory calibration and default profiles. The issue occurs regardless of any external displays being connected. This is not related to True Tone, Night Shift or anything like that.