Hi ​@Claire G  - any chance that the device that you've used for the run recording has time/date set incorrectly?

Also, it might help if you could post links to the two runs (both the correct one and the run seemingly from 2017), someone can have a look whether there's anything unusual / wrong. 

Here are the links:

https://strava.app.link/bxQNdsx2bSb  (Today)

https://strava.app.link/o2FfBEH2bSb  (Apparently me in 2017)

thanks for any help!

Is it possible you purchased a used Garmin watch and the previous owner's activities are still on there?  If so, you may have unknowingly uploaded all their activities onto your account.  And by chance, they ran some of the same segments as you just did.  From what we hear, things like that have happened before.

So the two runs are similar but not identical - I thought the recording could have duplicated somehow but no, the pace is different, HR and weather information is missing on the old run, there's different shoes assigned etc, so rather it's what ​@JBW-Florida suggested - accidental upload from a 2nd hand watch. But it looks spooky indeed! 

Hi

the garmin was brand new in 2019.  So it can't be random data from that. 
 

it's a mystery!

whoa... have you had any pre-used garmin before this one? maybe the run got loaded in your Strava long ago - and now only re-surfaced as a “matched run” or something... 

(I’m tempted to ask at this point, “are you really sure you've never been to Madeira before?” 🫣)

Hi

I've only ever had new Garnins although I have given old ones away.  
 

I am beginning to doubt myself, but no, I haven't been to Madiera before.