After updating to 11.16 I regularly experience crashes of watch faces (IQ logo instead of a WF).
When I go to watch face selection mode - all WF with a weather complication (garmin weather data) are shown as black circles. WF without weather data - are fine.
Same behavior for WF from different developers.
After a reboot all works fine.
I have seen similar complains on reddit as well.
Looks like a firmware bug.