I am using N5244A PNA-X with A.10.60.07. 1 of these recently came back from calibration and now is exhibiting odd behavior. The gain seems to vary every time I change the internal receiver attenuator on port 2 when testing a 2 port amplifier device. For instance, for a particular measurement, I get about 50dB gain at a particular receiver attenuator setting. But when I change the receiver attenuator to be 10dB higher and re-run the measurement, the marker will show my measurement to have a 40dB gain instead! I have another PNA-X with the same firmware, but hasn't gone out to calibration and it is behaving normally, meaning the gain stays roughly the same regardless of what receiver attenuator value I use. This also affects other measurements like IM3 and spurious measurements. I checked the path configuration settings and they match between the 2 PNA-Xs. Is there something I can do to fix this software wise, or is it somehow hardware related?