BUG HRMPro PLUS stops tracking kcal after some time

Hi there, i am using the HRMPro PLUS without any other garmin device.

Here is the issue in garmin connect.

After i put on the device and do some workout everything works as expected, step count gets updated, hart rate monitor seems to work and ckal tracking seems to increase, e.g. active and passive.

However after some time the active ckal tracking just stops, there is nothing that can be done to increase the value while hart rate monitor still shows an elevated hart rate and also the step counter increases. For example i did a 30km bike ride after a workout but the active ckal traking would not change at all. It only started working again the next day but after some time the same thing happened again. I dont think this should be the case.

I allready returned the device ones but the replacement suffers from the exact same issue.