Hi ​@JoJ,

there can be many reasons, including e.g. your device’s clock being even slightly off. Here's a detailed explanation of how the feature works incl. some troubleshooting ideas: 

https://support.strava.com/hc/en-us/articles/216919497-Group-Activities

Many thanks for this Jana_S.  The Strava support team have given me a lot of detailed response as well though I still am not sure why my friends who I have been running with for years do not show up on my feed anymore

Well the feature itself does work. Whenever I join a race, I see a bunch of other runners as running “with me."

You might want to use the article I posted as a checklist of items that you need to verify. Is your phone/watch clock set correctly? Haven’t you changed your home address zone? Haven't your friends changed their grouping preferences? 

If you verify all possibilities one by one and still can't find the cause of the problem, it would help if you post links to sample activities (yours as well your friends’) that you believe should have been grouped but weren't. 

Thanks for this, I have checked all the info and it is correct but this is what I don’t see anymore (that’s not me BTW!)

​@JoJ  thanks for the screenshots but would you please post actual links to the activities? Including yours. 

Simply open your activity in your web browser and copy the link address from the address bar. It will look like this,

https://www.strava.com/activities/xxxxxxxxxxx
except instead of xxxxxxxxxxx, there will be numbers.

Please post one link for your activity and at least one for your friends.

thanks!