powdered snow lit by the sun/moon appears significantly darker than regular snow, however if it is lit by another light source such as a torch or glowstone block, or viewed with night vision it appears to be the same brightness as regular snow this inconsistency suggests that powdered snow is meant to be the same brightness as snow and is simply not rendering correctly 

Procedure for demonstration: place a line of powder snow next to a line of regular snow blocks and observe that powder snow looks significantly darker if you place a torch on the regular snow this effect goes away and if you drink a night vision potion the effect goes away as well.

Again while this could be an intentional feature it is unlikely given both that the problem goes away with night vision, and the fact that powder snow is meant to be difficult to tell apart from powder snow.

I find it unlikely that this hasn't been reported before, I'm sorry if it has but unless I've been searching for bug reports incorrectly this is the first. I could find

It probably affects previous versions but as I'm a console bedrock player I cannot access previous versions to test that