Relay fault - regular clicking noise

Occasionally I get a problem where I hear a regular (approx 1 per second) relay clicking noise from the inverter, and portal shows very low house, battery and PV power levels, although everything in the house is still working OK. This happens intermittently (perhaps once every couple of months) at random times. The only clue in the logs is a notification “Relay Fault”. I can usually clear it with a software reset via the portal, but a couple of times it has needed a full system power-down to restore normal operation. (Running Gen 2 HY5.0 inverter, s/w A0.915 with 9.5 battery, BMS 3015). Any clues as to a fix - am thinking software as the fault is not a “hard” fault.