Multiplus II charge cutting out when on RV generator

The equipment I am using is listed below. Here is my issue. My system has been working perfectly although I admit I had not run the generator for an extended time to charge batteries. Recently the batteries had run low so I started the motorhome generator. My RV is set up to automatically switch between shore power to generator when the generator is running. The generator is rated for 70 amps. I unplugged the shore power and set the Multi Control to charge at 30 amps (highest setting) to charge the batters as quickly as possible. After a short time, I noticed on the Cerbo GX that the charge system was cutting out. The shore power part of the display would go blank. It would then come back on at low voltage and slowly ramp up until it hit around 2000 watts and would go blank again and start over. This occurred every 15 seconds. I decided to do some experimenting. I dialed the Multi Control back to charge at 10 amps. The display showed Shore Power at 1050 watts. Turned Multi Control up to 15 amps, shore showed 1630 watts. Here’s where it gets weird. I turned the Multi Control up to 20 amps and shore showed 2010 watts. Turned up to 25 amps, shore showed the same 2010 watts Turned the Multi Control to 30 amps and still showed 2010 watts. Around this time the system started cutting out like before. I don’t get what’s going here. To be sure this was a generator issue I ran the batteries low and did the same thing on shore power. Even if the Multi Control was set to 30 Amps it did not seem to charge at over 2020 watts (16.8 Amps) although it never cut out when on shore power.

My Motorhome System

Victron Multiplus II

Victron Cerbo GX

Victron BVM 700 Battery Monitor

Victron Shunt

Victron Digital Multi Control 200

Victron Blue Solar MPPT 100/50 connected to 4 Suntech 175 watt panels wired Series/Parallel

Lithium batteries are JavaEnegy (Chinese) 300Ah LifePO4 battery (Two Batteries) Total 600Ah. Batteries are rated for max charging current of 200A each

So your batteries are 12V? What model/power is your multiplus? The generator is 70A @ 120V AC? So 8.4kVA?

Yes batteries 12V. Multiplus II 30 Amp. Generator plates shows 8kw