This appears to be due to a version change
@watou John Cocula Maintainer
This could be completely unrelated, but in case it’s not, this commit13 updated nrjavaserial from 3.9.3 to 3.12.1 three days ago.
See issue Nrjavaserial upgrade causes "Serial Error: Port /dev/ttyACM0 does not exist" - #3 by mhilbush.
It might be better to continue this discussion over there.