Nah, my money says that it's a little bit of something that is preventing full closure of the oil pump relief valve. At low engine speeds the pump does not provide much volume or pressure & it doesn't take much to bleed off enough extra pressure to bring it down into the 'light on' zone.
As revs pick up, the volume & pressure are enough to overcome the losses at this point.

Well, that's my theory anyway.

As for that back bearing thing in my engine, I suspect that it's a once in a lifetime problem.