I find this bug again, with the Ki-84.
Guys, something is amiss, because, I've never seen this happening with the Ki-84 before.
I think it has something to do with the arena time. Come to think of it, all the instances where the gunsight glass canceled out the sun... was during dusk or dawn.
I think some of the planes might have this problem, and it will only show when dusk/dawn conditions appears - which would explain the reason why these bugs are so infrequently reported despite the obviousness.