I have some activities categorised as 'Trail Running' or 'Track Running'. On these activities, despite wearing my HRM-run, the app doesn't show Cadence/Vertical Oscillation/GCT data. In Garmin connect it shows VO and GCT but Cadence is blank (which I guess is a related bug). Sound like the app needs to be set up to recognise the running subcategories as part of the running category!
HTH
CW