I can't believe this thread is still going.

I stopped following it when it had about 50 pages or so... (and no I haven't read the last 130+ pages).
I hope the OP is happy with the sh#%storm they started here for what might only truly be affecting a tiny subset of users. The 12 line has panels that are tuned less white, period. If that's not obvious by now...
True tone is also programmed extremely warm, furthering the effect. And turning true tone off makes it cooler, but doesn't help make it whiter, because all it's doing is dropping the yellow and bumping up the blue. But no matter what, it's going to look less white than previous models (
especially LCD's like the 11, XR, 8+ and prior, which a TON of people upgraded from).
The fact that we're a couple of months into this now with new batches and shipments from Apple and nothing has changed, and the fact that software has not changed anything, should be further proof that this is the way Apple intended it. Most of the people adding to this thread (not all, but most) are looking at how yellow it looks
with true tone on, and comparing to their previous less-yellow iPhone, and then thinking they have a problem because of this thread when they likely don't have a problem at all.
And again, I'm not saying there isn't an issue with a few, but it's not some widespread major problem like this thread makes it appear to be.
If you don't like the warmer screens on the 12 line, then you'll want to stick with the previous models. Or, try ignoring your old phone for a week and I bet you won't even notice any more, or might even like it.