Low tempture screen color fade

Not that I noticed, but I would say that's somewhat normal behavior for an LCD screen that's in extreme temperature (hot or cold). As long as it returns to normal once it's warm again, I wouldn't worry about it, unless the fade is extreme enough to be causing readability issues. In your photo it looks pretty mild.

What’s with the altitude?

have the same one mine. also blue tint display. unbelievable how bad the display is

That 1mm band is the photovoltaic strip where most of the solar power comes from. It’s different to the watch screen so that might account for the different shades of black.

From DCRainmaker’s website.

The watch being discussed in this thread isn't a solar model.

The non-solar models do not have that lighter-colored strip around the edge.

Good point, well made!

He is pushing F6 to the limit. 

My guess is that, since baro is 0, he is an astronaut complaining about the watch in the international space station during an outside walk.