Parkrun yesterday, official published time 25' 24", manual stop watch time 25' 14" - didn't seem like 10 secs to get to the start line after the go, but fair enough.
Now Strava
First off, it's overall summary was 5.1k in 26' 04". Not fussed about that, as I didn't stop it until after I'd had my barcodes scanned, and "pause" is switched off 'cos it's mucked me about before.
Next, it recognised the run as a 5k "segment" someone had done before. It gave me a time for that segment of 25' 06" - things are looking up
Then I added up the separate split times for the first 5 ks - came to 24' 55"
And finally it gave me a 5k PB of 24' 47"
The only explanation I can find (while I'm on top of the world looking down on creation) is that the course (Portsmouth Lakeside) takes you through a subway under a dual carriageway four times, so maybe the GPS loses lock and also loses the time spent "underground".
Not looking for answers, but thought I'd share the experience for amusement's sake ……...