Oven trips Breaker on when using AC500 as UPS

I got a new stove/oven and now when I try to turn on the oven the breaker constantly trips if my AC500 is acting as a passthrough in UPS mode. It’s a Gas Stove/Oven so it’s just a 20 Amp breaker, but .5 seconds after the Oven kicks on the breaker trips. I’m assuming it’s somehow tied to the ground when the sub panel is being fed from the Batteries, but I’m open to suggestions. It worked fine with my old oven.