Eaton Hydrostatic pump - charge pressure 500+?

[awol]

I have a set of new Eaton ALC series hydrostatic series 2 pumps. I have guages in the A and B gauge ports for system pressure. We are experiencing high charge pressure in one of the pumps. I have joined A and B ports together and the gauges read 500psi. As I increase RMSs to the pump, the pressure on both sides of the pump increase up to 800psi. I have deadheaded the A and B ports and one gauge reads 500psi, the other went to about 1100psi. The internal charge pressure relief is set at the factory at 300psi. This is what I expected to read at any rpm, not a higher pressure that increases with RPM. The Eaton rep in on his way but he cannot explain this either. Has anyone experienced a similar situation? Could the relief valve have contamination and prevent the relief?
The pumps are controlled electronically and I have disconnected the controls to prevent any stray signals.

Thanks,
awol