question

Hi from the USA, @yanmpoyi. When the inverter turns off, are you seeing the Overload red LED lit solid? If so...and especially if the output AC wiring has been newly installed or recently modified...here's a theory:

Wires can move a bit when they heat up & your wires may be moving enough to develop an AC short circuit which then goes away when they cool down. Inverters often do an overload shutdown quicker than the AC circuit breaker can trip but in your case both reactions may be occurring around the same time.

I'd look for a "hot" that's somehow managing to brush ever so lightly against the metal chassis or wiring box. A tiny contact is enough.

Sunny Days~