> Kernel: Linux 4.16.0-1-amd64 (SMP w/8 CPU cores)
It seems that there is a reported bug on 4.16.0 about this:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=898021
You might want to downgrade to 4.15.0 just to be sure that you a are affected
by the same issue.
Happy hacking,