You've eliminated the most usual cause, a faulty pressure switch. The other usual suspects are that the oil pump tolerances are out of spec, a bad drive gear oil seal, or that the oil galley plug is backing out (any aluminum particles on the oil screen?)
Under the circumstances, it would be unwise to just continue to ride it without knowing whether the oil pressure is actually low or not. The consequences include failed bearings and engine seizures.
Hook up a pressure gauge to where the sender mounts. Evoluzione sells an inexpensive one.