So I am pretty sure its the pump cavitating as was suggested. All signs point to this. Thank you. But I can't seem to resolve it. I went ahead and re-bled the lines and verified that my cold pressure was at 12 psi before starting things up. When running the boiler the gauge reads ~20psi which from my understanding it just fine. So I am out of ideas. The other aspect is that this is my third pump in 12 years. So I suspect there could be a basic system issue at hand (under sided?) as everything I read says the pumps should last decades, not 5 years.
Unless anyone else has some thoughts I think I will wait this one out and replace when the time comes (could be a few years for all I know). The plus side of this is that I didn't know anything about my heating system until all this research and I am confident I can swap out the pump when it happens.
I would say 3 pumps in 12 years is a sign of a bigger problem . . . as far as I can tell (and the dust seems to agree with me) this house is on its original circulator pumps at ~26 years.
While you may wish to wait to replace the pump, I would encourage you to do two things; first research what pump you need (size, flares, connections, HP, ect) and second which features you may want (split phase vs ECM, delta-t, delta-p, ect), that way you already know the model you want when the time comes. And second, if you believe the pump is likely to fail (your history tends to point that way) consider purchasing the pump now and having it available; last year I came home from work, notice it was already negative 15 F outside and falling, I determined that a motor had failed in the heating system, and that might have stocked a replacement was closed. . . a job that I have done before in less than 30 minutes with a ~80 dollar new motor cost me much much more to have heat as the temperature again.
