PV Production Drop to ZERO

I have GW6000 ES C10 installed, suddenly PV production drops to zero on a good clear sky weather. It starts to draw from grid and battery.

After a few minutes, I decided to switch off the GRID (goes OFF GRID) then switch ON again, and suddenly the PV production returns to normal... and system operation back to normal.

Setting is Self-Consume.

This happened twice already this month.