Help Needed: Select + Start Buttons Not Opening Menu on Recalbox with Pi3 and Pandora's Box

[GetOldGaming]

Hi everyone,

I recently set up an arcade system using an eight-button Pandora's Box connected to a Raspberry Pi 3 running Recalbox. Overall, everything is working well, but I've hit a snag with the Select and Start buttons.

Here's the issue:

Select and Start buttons work individually: Both buttons function as expected when pressed separately. For example, I can use Select to add credits and Start to begin a game.
Select + Start together not working: When I try to press Select and Start together to open the Recalbox menu, nothing happens. This combination should normally bring up the Recalbox menu, but it doesn't.
Things I've Tried:
Recalbox Configuration: I've checked the controller configuration in Recalbox, and everything seems to be mapped correctly.
Wiring Check: Double-checked the wiring to ensure there are no loose connections or crossed wires.
Rebooting: Restarted both the Pi3 and Recalbox multiple times.
Questions:
Has anyone else encountered this issue with a similar setup?
Are there any specific settings in Recalbox that I might be overlooking?
Could this be a firmware issue with the Pandora's Box or a compatibility issue with the Pi3?
Any help or suggestions would be greatly appreciated. I’m really looking forward to getting this resolved so I can fully enjoy my arcade system.

https://imgur.com/a/5aBiyt9 (images of hardware)
https://www.evernote.com/shard/s550/sh/757aa191-4981-3e84-4a02-df2a0f819f2d/OrSCg7D2SUwuawIv3JWoY57eqrXUUxHh1khyv2ont0KPyzFnM20aeYyxEA (Recalbox.conf)