Hi, I just ran into this bug when starting my work (stretch with very few backports packages) machine after a vacation.
I had installed a backports kernel (linux-image-4.11.0-0.bpo.1-amd64) and must have booted into that for the first time. Rebooting into linux-image-4.9.0-3-amd64 made the problem disappear. Cheers, -Hilko
