MongDB 3.6.15 was running as a part of Graylog in a Docker container. After several weeks, the assertion happened as shown in the attached log.

The error starts with:

2020-02-02T11:14:02.046+0000 W FTDC [ftdc] Uncaught exception in 'FileStreamFailed: Failed to write to interim file buffer for full-time diagnostic data capture: /data/db/diagnostic.data/metrics.interim.temp' in full-time diagnostic data capture subsystem. Shutting down the full-time diagnostic data capture subsystem.