The A5 receiver may be saturating. The received signal from the C5 and EVM both look really high, so you might try reducing the C5 power level if possible. Other options are to adjust the orientation of the C5 relative to the A5, or rotate the A5 clockwise about the mounting pole.
Based on the signal strength at panels 1-4, We can tell that this C5 is very close to A5 panel #4 with an offset toward panel #3. It is typical to see a 15-20 dB difference between adjacent panels, and -100 dBm at the panel pointing in the opposite direction (180 degrees). Please see image below.