Transferring files from Polar Flow to Garmin Connect caused data duplication in Stryd Power Centre and Strava

     I found a tutorial here on the forum on how to transfer data from Polar Flow to Garmin Connect, which works great and thanks for that!

     I have only transferred part of the data so far because of the following problem with duplication of workouts in Stryd Power Center. I have linked my Garmin Connect to the Stryd Power Center, where Garmin automatically sends and saves workouts.

     However, when I got the workouts from Polar Flow into Garmin Connect (this data was already sent once by Polar to Stryd Power Center by linking accounts), the new data was duplicated in Stryd Power Center and it made a horrible mess in Stryd Power Center (same data again sent there by Garmin).

     Anyone have any ideas how to prevent data duplication in third party apps please?

     I thought of disconnecting my Garmin account from Stryd while the data is being moved, but I need to keep it connected and once reconnected I'm worried about the newly uploaded data being transferred retrospectively again.

I think everyone who has transferred data already synced by Polar Flow to Strava and then transferred that data from Polar Flow to Garmin Connect, which duplicated it to Strava again, has faced the exact same problem.