FitContributor breaks multisport activities

I've written a data field that implements the FitContributor method to write additional data to the FIT file.
It's designed for running, but that shouldn't really prevent it being used in multisport activities. I don't have a multisport capable watch myself, but a user has reported that when my data field is used in multisport mode, it causes the Garmin Connect activity to appear blank.
e.g.

A running activity created with my data field on a Forerunner 735XT
https://connect.garmin.com/modern/activity/1553960911
Everything looks fine, you can see the additional IQ graph and data
Two activities created in multisport mode with the data field (again, FR735XT)
https://connect.garmin.com/modern/activity/1553950709
https://connect.garmin.com/modern/activity/1553963598
The stats data and graphs (speed, HR, etc) are all missing
cf. a multisport activity from the FR735XT without the data field
https://connect.garmin.com/modern/activity/1500194726/5
Stats data, graphs all look fine

Has anyone else seen this problem? Garmin aware of it? It looks like a bug to me.

Former Member over 8 years ago

Hey. So I've got some movement with the Connect Web Team on this right now. They have a customer support ticket open about it through our normal product support channels. This means two great things:

1) Real world customers are using your data fields and they see this a core feature. This only goes to show the strength and impact your content is bringing to our platform. In short, thank you.
2) When customers get the ear of our developers it tends to go a long way. I can say that I have a developer with users having issues with "xyz", but when customers on the other side of a phone are saying that there is money on the line, ears tend to perk up.

In conclusion, I know that fitContrib data and Connect have been a long batter for our devs and platform, but I think we are on our way to real progress on these issue. I've let them know that we've reported this before and linked all of the appropriate tasks. We so appreciate your patience and hard work.

Thanks,
- Coleman