I'm making a dining room table out of white oak. We used 60 grit sand paper, and then sanded down finely after. We used exoxy to fill in some cracks and then a polyurethane coating (no stain to keep the natural wood color).

We've only put the polyurethane on the bottom, which came out extremely blotchy on the 2 outside pieces of wood. There are distinct lines and patches and I have no clue why. Any tips on what we have to do to the top?