HRM-Pro standalone - Active calories not included in overview in Garmin App

I use the HRM-Pro standalone for my Cardio activities, for cycling / running I use my Forerunner 265.
On itself both devices work fine, I can easily transfer my data the the Gamin app.
But the processing of the data, especially the burned calories is not according with what I expect.

* The Problem
When I check my calories in the overview (e.g. by day):
- active calories recorded with HRM-Pro are not included in the "burned calories" overview
- but they are visible in "latest activity"
- What am I doing wrong, how can I add them to the overview?

* Devices:
- HRM-Pro Plus
- Forerunner 265
- Garmin Connect App for Android

* Detail
The HRM-Pro is coupled with the my 265, everything works fine.
But this is what happens:
- Use the HRM-Pro standalone during cardio training
- After training download the results to my 265
- Sync my watch with the Garmin App
Results - in the App:
- Heart rate during workout is visible
- "Cardio / Statistics" shows the active calories burnt for this workout, e.g. 700
- But in the "At Glance"/"Burned calories" it shows only : 44 (!?)
- Conclusion: the heartrate/calories recorded by HRM-Pro are not included in the total result
During other activities, like cycling / running where I use the 265 watch to record my activity the burned calories are added correctly "Burned calories" overview