Thanks for the response! I tried to answer the questions below:
How much of a pressure rise do you see when the solar is on? 10-11 PSI
How is your solar laid out? Height above pump, distance from pump etc. Roof mounted 20 feet up, equipment (filter, pumps, etc) are about 2 feet from the mainline ascending up to the panels.
Are you directing all of the water flow through the solar? Yes, all water is diverted to the panels.
I took the valve apart to see if the issue was with the valve and I don't think it was. I noticed that when the booster pump is on and driving the sweep and the solar is off there are no air bubbles. When the solar is on and the booster pump is off there are no bubbles. It seems to only be an issue when both the booster pump and the solar are on.
I've been on the roof (not my favorite thing) and I don't see any leaks, and all the caps look good.