Velbus entities don't show up, component seems to be working

Home Assistant release with the issue:
0.87.1

Last working Home Assistant release (if known):
0.78

Operating environment (Hass.io/Docker/Windows/etc.):
Hass.io on RPi 3B

Component/platform:
Velbus

Description of problem:
The entities don’t appear to be present, while I can confirm communication to Velbus on start via the leds. The log shows that some modules are not yet supported, which clearly indicates that the detection is happening, but no entities become available.
I also see an error message SyncWorker stopped for that component.
It suddenly just stopped working.
I did a complete reinstall of Hassio, and still the situation didn’t improve, which seems to point to an external cause, but I could not find any.

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

velbus:
  port: '\dev\ttyACM0'

Traceback (if applicable):

2019-02-13 16:58:51 DEBUG (SyncWorker_10) [homeassistant.components.velbus] Shutting down

Wed Feb 13 2019 16:59:14 GMT+0100 (Central European Standard Time)
Module VMB2BLE is not yet supported.