The last time I created a segment it showed all the past activities. I'm not sure but if it's as you say it could be a way to declatter the segment tab from "not fare" activities

It was the same for me before, but last week I’ve re-created the segment 3 times - past activities are not there, only activities after segment creation.

​@Tych - How long have you waited after creating the segment?  Recently, I have seen it take 24 hours or so (maybe more) to fully populate the segment leaderboard for a new segment.  It will start with the most recent and eventually work its way back.

I’ve waited for couple of days. Nothing was populated. Only new runs after creation were counted.

Does this impact all your newly created segments or just the one? Maybe it’s a new track where nobody rode before.

I’ve tried yet with only one segment - it’s a new running route in a forest, nobody ran it before April, but in April we had a race there, so there are dozen of attempts at least. And all new attempts after creation of the segment were shown in stats.
Will try with other segments and activities.

I’ve created two new segments bike and run - stats were updated immediately. Then I’ve tried to edit the original segment (actions → edit → save) and historic data was populated! Seems it was some bug.

Question is closed.

came here for the same problem, noticed happening since months, always went smooth before, so it is definitely a bug. Thanks @Tych for the woraround