Tailsitter motors engage with mode change to FBWA while Ardupilot is disarmed

I’m starting early bench testing of a tailsitter using a Matek H743-Wing v2 and ArduPlane 4.3.1. The FC powers up in QLoiter mode and as expected has no throttle response with ArduPlane disarmed. Keeping it disarmed, if I change the flight mode to FBWA the motors suddenly spool up to what sounds like around 50% throttle and do not respond to throttle input. If I change back to QLoiter, they shut back off. Thankfully I’m a long way off from mounting propellers. I know there are several settings that set thresholds for arming, but when Mission Planner is clearly blinking in disarmed mode, there should be no condition that causes the motors to turn. I’m still new to ArduPlane so I am open to feedback. Here is a link to my parameters file. If someone can take a look and offer any advice, I would be grateful. ArduPlane Params

Upon further testing, I found that what was happening was changing to any fixed wing flight mode would set the servo outputs of the throttle channels to the trim level. I set these up after setting the q parameters, so they stayed at their default trim level of 1500 instead of 1100. It seems that when disarmed, only the radio input for throttle is ignored. If the FC alters the servo outputs for throttle, those values are sent to the ESC even when disarmed. I’m not sure this is entirely safe, but now I at least have my FC configured where throttle outputs will be below the ESC minimum for all flight modes when disarmed.