Try attaching a known straight edge along the side of the board, and running the straight edge against a flush trim bit bearing. The board may simply be following its own shape along your table and fence.
I'm not slow, I'm pacing myself!
Isaiah 44:13 Another shapes wood, he extends a measuring line, he outlines it with red chalk. He works it with planes and outlines it with a compass...
Usual kit: Table saw, band saw, dual base router and table, lathe, various saws, planer, sanders, and a multitude of hand tools.