Aftermarket Inverter Draining 12V Battery While Off?

Hello,

I installed a 1000W Renogy AC inverter into my 2015 Prius Plug-In. It's connected directly to the 12V AGM battery in the trunk. I use it to power some electronics while parked in READY mode.

I noticed that sometimes, despite the inverter being in the remote mode with the remote off, or fully "off", it seems to be intermittently draining my 12V battery. This happens while the car is parked while off and I step out for a few minutes or hours. It is no longer able to put the car into READY mode. I keep a jump pack in the car and have had to use it several times to start it fully. Sometimes it won't happen at all and everything is fine.

Does anyone have any thoughts on if there's something wrong with the inverter or my install? I've been on a long road trip and haven't had a chance to look at it yet. I hope to install a low voltage disconnect switch but it seems very unusual for what should be a top-spec inverter.