Sand down the final finish with a 220-grit foam sanding pad, and then add another layer of General Finishes High Performance PolyurethaneTopcoat. Apply liberally than you did previously without heavy back-brushing.
Let the topcoat self-level a bit - it will tighten down as it dries.
If it's above 80°F or if the humidity is less than 70% in the space you're working, we recommend adding 10% GF Extender to the topcoat to improve open time.
Watch how to apply a water-based topcoat to a large surface with a paint pad applicator here.