Incorrect distance syncing to Apple health

I just re-check filtering "Connect" source for walking+distance data.

As you can see from the screenshot, and the same goes for other metrics like resting calories, untile the red line the values are correct. Past that the training get summed several times each day.

Maybe it was fixed in a previous release like Garmin said, than the bug reappeared on February. Each data source has the option to refresh data for the past.

That may be the case for you, but if you look at the posts of others, the double-count distance issue has been consistently present since at least October last year. There is a difference between having multiple entries and having a single entry with the distance included twice. Many of us have provided screenshot after screenshot, diagnostics logs galore and Garmin folders aplenty to Garmin over the past several months. The one thing that has been consistent is that the distance reported in the final day entrry by Apple Health exceeds the total distance in Garmin Connect by the distance of a recorded run.

The duplicate entries started in February; but the fact that Garmin Connect has included run distance twice in the total has never been resolved even temporarily.

Same issue for me. 
Running distance is added to apple health at every sync of watches with garmin connect.  

very disappointed in my purchase of 945. 

Being a bug in GC you would have hade the same issue no matter which Garmin device you  had.

On the upside as soon as Garmin hires a competent iOS developer all of its watches will correctly work with Apple Health.

Agree. 
However, this simple issue has not been resolved for more than a year according to the forum records.

With this level of attention to details how can you be sure that all other data collected within devices is accurately measured, stored and presented? 

More interesting finds. It seems Garmin developers didn't really understand how HealthKith APIs work.

When saving say a workout, you tell the times (beginning, end and so on) and you can "attach" relative data, such as, for a run, active calories and total distance. When you open the workout on Apple Health, troll to the bottom you can fine these other metadata fields.

To partially fix the atrocious poorness of GC data saved on Apple Health I decided to sync some of it by linking my Str*va account and letting it save data instead of GC.
With Str*va all metadata for a workout is correctly linked, while for GC it just shows nothing, because their developers don't know how to do that.

Take a look at these screenshots (in Italian, but easy to understand the context):

Here Str*va compiles all date/time fields correctly, so that it perfectly coexists with move data coming from my iPhone, not duplicating the same from two different sources.

Here Garmin Connect adds the cumulative walking+distance(+bicycle because their not competent) data with the same date/time timestamp for both adding to Health and the time in which the user walked/ran the distance. Missing the time interval Apple Health correctly ingest it as if all the distance has been travelled in one second, thus it gets summed the other data coming say from the iPhone itself.

Finally the icing on the cake. The day after, when syncing in the morning, Garmin Connect adds all the distance, plus what was not already recorded between the last evening sync and midnight and write all over again at 10:59:59 PM (22:59:59 in 24h format) because they probably don't know how to fetch 11:59:59 on DST, once more without a time interval, so all the distance once again travelled in just a second.

Totally agree. I come to the same conclusion. It seems that their algorithm contradicts with Apple Health requirements which were successfully implemented by many other health apps. 

BTW my walking/running distance for yesterday is growing! 
0.99 is a distance of yesterday run

6.39 is total distance for the day from garmin connect

1 duplication in total amount (7.3 instead of 6,4)

and many repetitive records of workout distance that continue to grow

 User Lambronico has provided very detail analysis of the issue. Can you please specify approximate timeframe for resolving the issue? 

I believe that a lot of users (all garmin users owing iOS devices) is affected by this issue. And Garmin connect is the only sport app that has this amount of bugs in healthkit integration.

Having sent my Garmin for a battery check, this morning I tried to basically track my indoor cycling with my Polar H10 strap together with their app. It's been a nice experience and, as you may guess, Training time + calories + heart rate (a value per minute) all showed up in Apple Health, linked together, with absolutely no issues.

So it seems we all chose the wrong horse to bet on. Any competitor, from the bigger ones to the indies just managed to get Apple API to work properly. Anybody but Garmin.