I manually upload the files from my various devices and noticed today that the last few have had the device set to unknown. It worked with the FIT file on Thursday: https://connect.garmin.com/activity/1022435842 but not since (ex: https://connect.garmin.com/activity/1029598752).
Both show the correct device when uploaded to Strava. Hopefully this can be addressed and repaired for the impacted uploads without having to remove and resubmit them.