u/Any-Juggernaut-3121

I have a secret nailed Sydney blue gum floor that I have had sanded and stained using feast Watson proof tint to a dark black brown colour (normally Sydney blue gum red colour)and then covered with three coats of water-based polyurethane. After the second coat it looked fine, but after the third coat you can see the clouding and brush marks and white effect in the various photos. 3rd photo is jarrah in the bathroom, same issue. What has my Floor Sander done wrong? What can I do to fix it? Also photo 4 which has a test area he did where you can see the cloudiness forming in the pool of Poly. I think he may have applied to too thick.