RGBcommander vs. GPIOnext

[KSack]

I have a Raspberry Pi 4B with original power supply and heatsink + ventilators.
with 2 ControlBlock's from Petrockblock, to use 2 NES controllers and 2 SNES controllers.
I also use ControlBlock to power up and shut down the retropie
I also have RBGcommander running

I've recently added GPIOnext to have some function buttons.
Since then every time when I have used a function button, on shutdown, the deamon from RGBcommander has problems to quit.
The message "a stop job is running for RGBcommander" shows up (with a timer of 90 seconds) I've already used the shortcut to reduce the time to 10 seconds, but it's always better to solve the problem instead of using a workaround ;-)

sudo gedit /etc/systemd/system.conf

change the line #DefaultTimeoutStopSec=90s (and remove the comment of the line)

systemctl daemon-reload

I'm wondering why RGBcommander hangs and how I could solve this.

I've checked the log file of RGBcommander, and it looks like the tool starts hanging from the moment I pushed a function button... (button pushed after 21:25:44)

pi@retropie:~ $ tail -f /usr/sbin/rgbcommander/rgbcmdd.log
23/08/21 21:20:32 [INFO] [startListening] selectserver: listening on IP 0.0.0.0, socket 22
23/08/21 21:20:32 [WARNING] [startListening] selectserver: bind failed, error: 98
23/08/21 21:20:41 [INFO] [RGBAstart]random animation chosen -> Pattern18_32
23/08/21 21:20:41 [INFO] [RGBAstop] animation stop -> success ...
23/08/21 21:20:41 [INFO] [setRGBAspeed] RGBA Pattern18_32 speed set to 100
23/08/21 21:20:41 [INFO] [processMonitor] mm_percpu_wq is running
23/08/21 21:20:41 [INFO] [RGBAthread] rgba Pattern18_32 play back start at speed 100
23/08/21 21:20:41 [INFO] [RGBAthread] rgba Pattern18_32 playback stop -> anim runtime ->  0.000293648s
23/08/21 21:25:44 [DEBUG] [rgbcmddMsgQueue] msg from rgbparse -> emu -> mame-libretro -> rom -> 88games
23/08/21 21:25:44 [INFO] [rgbcmddMsgQueue] waiting for process retroarch to appear...
23/08/21 21:28:02 [INFO] [signalHandler] interrupt signal (15) received
23/08/21 21:28:02 [WARNING] [signalHandler] termination request to the program raised - terminating now! - exiting normally

Does anyone has any ideas?