Double check your GIMX profile button configuration and make sure it detects all of your button presses properly without any conflicts.
I'm using a separate Fanatec CSS H-pattern shifter *AS WELL AS* a separate sequential shifter from Quiafe it's working OK. However, if GIMX for some reason does not recognize the inputs from your shifter, you might have to use a third party PC app such as SV Mapper:
https://theairtacticalassaultgroup.com/forum/showthread.php?t=10901
I'm using a separate Fanatec CSS H-pattern shifter *AS WELL AS* a separate sequential shifter from Quiafe it's working OK. However, if GIMX for some reason does not recognize the inputs from your shifter, you might have to use a third party PC app such as SV Mapper:
https://theairtacticalassaultgroup.com/forum/showthread.php?t=10901