Hello,
thanks for letting me know. I'm not a GSX pro so please be patient with me in that I do not automatically know "what you need".
* I use the FlyByWire A32NX (both development branch as well as stable v0.8.2)
* I don't set any payloads within the plane (MCDU etc.), all the payloads come straight from SimBrief which generates (I think) a random payload amount within specific thresholds?
* Before any flight plan is loaded onto the MCDU I activate the BATT/EXT PWR, APU and the lights, then I request boarding through the GSX menu
* THEN I load the SimBrief flightplan by using MCDU MENU - ATSU - INIT* and INIT - INITIAL REQUEST*, but at this time passengers are already boarding and cargo is loaded onto the plane
* GSX always shows me a passenger number between say 120 and 186 in the top left corner of the MSFS window
* But the passengers arrive only in 1 large + many medium buses in 9 out of 10 cases
I can provide you more information if you can specify what exactly you are looking for.
Thanks for helping me troubleshoot!