Eye adaption when using Auto Exposure Basic breaks when window size changes

This isn't really a recent regression, I think it's always had this issue but it's very annoying.

I also noticed that if I go fullscreen with the viewport, then back down to a smaller one it will be overbright.

1. Set up some Auto Exposure settings in your PP Volume and use Auto Exposure Basic

2. Try various window sizes, notice the exposure changes drastically,

See attached screenshots