Training effect not captured

Hey team,

Running a F6 Sapphire with 19.20 update.

I've just got my hands on a paddle modified concept2 erg used for dragon boat and outrigging conditioning.

Today I ran a 30min piece with an arm optical HRM sitting in Z3 throughout. I used the default 'indoor row' app to capture the session. Garmin stroke rate was on par with the PM5.

When syncing, there was no movement to the training effect. I have gone on brisk walks and captured some kind of TE data.

Any thought on what might be the issue?

Many thanks.