Walk logged as sprint, now my Training Load is stuck

Hoping someone can help with a really frustrating bug on my Forerunner 255.

The other day I went for a simple 8km walk. My heart rate never went above Zone 2, but the watch processed it like an all-out sprint, giving it a massive 274 load and a crazy 3.5 anaerobic score.

This completely wrecked my Training Status, so I deleted the activity from everywhere. The problem is, the 274 load is still stuck on my account a day later, and all my stats are still messed up. It's like a super-hard half-marathon effort, so as I continue my regular running without taking a recovery break from this, that'll be my training status ruined for months and constantly coming up against strained. 

I've tried all I can think of – rebooting the watch and phone, syncing with the app, syncing with Garmin Express on my computer – but nothing will clear it. 

Is there anyone from Garmin who can help reset this? The data seems to be stuck on your side.

I'll attach the screenshots showing the ridiculous stats it gave my easy walk.

Thanks.