I deleted a segment yesterday that I created - had a bit of a running battle with another cyclist where we have swapped KoM a few times. He took it back on Tuesday by 2 seconds (1:58 IIRC) about 23 mph. I then did it on the way home yesterday and smashed his time, averaged about 25-26 as I had half an eye on my garmin. Got home and it had logged 2:33 for the segment.
The issue was that the segment finished very close to some lights. As I was waiting at the lights it clearly thought i hadn't finished the segment.
I deleted it, then recreated it to be a bit shorter. The good thing is that the guy is still KoM on the recreated segment (by 1 second) so I haven't taken his away unfairly.
I suspect it might confuse him to see his KoM was done in July, rather than his latest ride on that segment (this Tuesday)