For 7 years we've had a ZWC1300C washer which happily run from either our Onan pure sine wave generator or from a Victron 3000 combo with engine running with no problems. The drum bearing failed so we bought the current replacement, the ZWC1301C.
This works fine from the generator but on the inverter it will wash and pump out but not rinse or spin. It seems to get to that point and then the drum just moves back and forth with a dribble of water coming from the drain. If you open the door, the wash is hot but still with some detergent in it. Change the programme to Rinse & Spin and it will rinse normally and pump out but not spin. Switch it to spin and it will spin up to full speed of 1300rpm.
On the old machine this happened once when I programmed the inverter to the energy saving mode. Programming the mode out and it washed and spun ok. I've checked via VE Net and AES is off. The only thing I can see is that the frequency seems to vary between 50.0hz and 49.9hz.
This is all on a 60 degree standard wash with the quick option selected which knocks 20 minutes off the time.
Now trying a 40 degree delicate wash which has taken 55 minutes on the gennie. Will see what happens and report.
If the suggested plain resistive load doesn't work double check there are no other fancy inverter output features programmed other than AES, that might compromise.
No specific help I know but mine works fine with simple Sterling Combi PSW inverter.