Single 'Run' activity will not sync with Strava - 'Walk' (before and after) synced successfully

I went for a walk this morning and the activity synced successfully with Strava.

I recorded a run and the activity won't sync/appear in Strava.

Went for another recorded walk, and this synced successfully with Strava.

I've tried disconnecting and reconnecting from both apps.
Is there a way to force the sync of an individual activity?

Here's the actiity link: connect.garmin.com/.../8250547915