Tempo graph is empty

For about 2 weeks now, after my run, the Garmin app does not show the tempo graph, although I can see it on the watch and also on the WEB version.

I tried to sync, to sign out and reinstall the app - nothing helped.

When I go for a walk, it does show the tempo graph, but not after a run.

How can this be fixed?

Thank you in advance,

Karinka