Hi, we discovered a strange behavior when uploading duplicate activities on Strava. We use the endpoint Post /uploads in order to upload activities on Strava and there is a case when for example a user tries to upload twice same activity and we have on our side the following handling: if the response from Strava is 400 and the message response contains "duplicate" we are providing to the user a message saying that "the activity is already uploaded", but we observed that for some accounts when we try to upload duplicates activities we receive 201 from Strava meaning "activity successfully uploaded".

Strava accounts observed behavior:

• for new Strava accounts seems to receive the correct response 400 in case of duplicates (e.g Strava accounts created for example today or 3 days ago)

• for old Strava accounts we receive 201 in case of duplicate requests (e.g Strava accounts created one year ago or 3 months)
• but after some time (2 days - 1 week) also for the new accounts we received 201 in case of duplicates -> we don`t know exactly the time range

Note: The settings of the Strava accounts are the same, the default ones.

We did some tests on 6 Sept 2023 on the following accounts:

Old account - https://www.strava.com/athletes/104900587 member since: June 27, 2022

• the response from Strava in case of duplicate activity upload is incorrect (201)

New account - https://www.strava.com/athletes/124063771 member since: September 6, 2023

• the response from Strava in case of duplicate activity upload is correct (400)

On both accounts was uploaded the same activity.

Can you please provide an input about this situation? Is there maybe a known Bug on Strava side for this case?

Thank you in advance!