Using a oil modified poly, the 3rd coat was put down, looks great except for a couple spots there is a small haze or cloud in the final coat? It been a week and it's still there. Any solution to fix other than sand and refinish the entire area? Also there is a small brush Mark where the poly tacked up, I was thinking could wet sand and polish?

The second problem, with the brush mark: I take a sharp scraper, and use it to peel off any overrun. I take it down to where I can't see any line left. Then I abrade it with either 240 or a maroon pad, and brush on some of the poly from the mix I used for the last coat. If you don't have any of that mix, try to find a quart with the same lot number as the ones you used for that coat.

Getting the same lot number is more critical if it's a satin or a semi-gloss finish; less critical if it's gloss. For a small area like that, a difference in sheen is probably not going to be that noticeable anyway.

For the first problem, with the haze/cloud, I'd need to see a picture. I don't think I've ever had a problem like that, but if I see a photo, I might recognize what you're trying to describe. On a larger area, touch-ups of any kind are going to require that you match the sheen of your original mix as closely as you can.

Here is the spot with the brush Mark



Here is the cloud, on the right

Here is the spot with the brush Mark



Here is the cloud, on the right just above the light reflection.

It's been there 2 weeks now.

Whatever caused the cloud, it doesn't appear to be a surface problem that can be fixed by scraping/sanding and touch-up. As you said, all you can do is sand that spot down to bare wood, and then re-stain it and build up the coats again.

You can try to apply polyurethane over that area, just to see if it improves it any, but I don't think that's going to help.