/dev/ttyACM1 randomly became ACM0

I noticed Zigbee stuff stopped working. I have a CC2531 plugged into RPi4 USB port. It was set to use /dev/ttyACM1, yet SOMEHOW, the plug (that I haven´ t touched in like a year) became /dev/ttyACM0. Upon changing this in the zigbee2mqtt config, all is working again. I repeat, I didn´t touch either the physical Pi NOR the Z2M config at all.

Super weird, any further explanations?

Sometimes they just do.

you can prevent this from messing up your system in a couple of ways.

the easiest is to just use the “by-id” for selecting your usb device. the id will never change even if the device path changes.