Hi Jeroen,
Thank you for reporting this issue. There is issue in code generation script that causes that when label and identifier is used for ADC pins in Pins tool then the GPIO_PinInit() code is updated to use GPIO symbols expected in pin_mux.h, however, the symbols are not generated to the header. Attached please find patch resolving the issue.
How to install the patch:
MCUXpresso Config Tools v7: Go to File > Data Manager > Import, select the attached archive and choose processors you want to update
MCUXpresso IDE 11.1.x: Go to Config Tools > Data Manager > Import, select the attached archive and choose processors you want to update
After installing the patch please restart the tool and update the generated code using Update Code button.
Regards,
Lukas