I put on Chameleon polymer combat armor right leg ( upgraded legendary armor )

Armor increases stealth when you stand still.

I equip it and the pip-boy screen goes blank while the perimeter of the pip-boy remains.

I unequipped it and pip-boy returns to normal .

Vanilla game has never been modded

AMD R9290 x2 in crossfire. 16.1 drivers

This is a known behavior that can be found in various threads here. It is believed that it is working as intended, at least by many players. As one person put it, you can view it as conflicting technologies (i.e., you can use Chameleon but you can't use the Pip-Boy at the same time due to technology issues between the two).

Of course, if it isn't working as intended, BGS may include a fix in a patch at some point, or perhaps DLC.