MC6 Pro only sends PC to HX Stomp when connected to a device (phone)

Hi everyone, my problem is the following: I send preset changes to my HX Stomp via USB and until recently this worked well. But then after assembling a bigger pedalboard and adding a few more devices to receive MIDI from my MC6 Pro, I have encountered a weird ‘bug’ that I just noticed yesterday for the first time: the PC messages are sent to the Stomp ONLY when a device (in this case my Android phone that has MIDI Editor app) is connected to the ‘device’ USB port of the MC6 Pro. The MC6 Pro is powered from my CIOKS DC7 using its 5V USB out with a Boston USB to 9V/1A power converter. I am not sure if this is a firmware thing, or maybe some MIDI routing problem that can be easily solved. Or maybe even a power issue. My current firmware version is v3.13.5. Wonder if anyone has experienced a similar situation, and thanks for any assistance!

Just a little update on this: I did a little reshuffle and changed a few cables and pieces on my board, including the power cable source for the MC6 Pro (switched it to a regular 9V output on the Cioks). Not sure if this was the problem but it has since disappeared. I did not make any changes to the settings, no firmware updates either, so it might have been a power thing.