Zen Master Badge

Were they all recorded on your device or did you add manually after the workout?

They were all recorded on my watch and then synced with the app.

Could you post a link to one of them? 

Yes, it looks all right. In fact, I just checked my records, and I did already 7 yoga sessions since the 28th April, and did not receive the badge either. It means there is either a bug, or some undocumented condition, like for example the mandatory use of PulseOx to measure the breathwork, or a minimal duration of the activity, or certain minimal drop of stress level during the session (all that is just a wild speculation). I tried manually adding poses, and respiration rates to all the yoga activites, to see whether it helps, but these ones did not make any effect.

I am afraid you'll need to contact the support to find it out. Let us know if you succeed.

OK, so I finally got the Zen Master badge after my today's yoga session. It was the 8th yoga activity since 28th April, and 4th since 1st May. So either you need 8 yoga activities, or it starts counting since 30th April, instead of 28th April, as stated on the badge.

I had the same exact problem and solution.  Today was my 8th yoga activity since April 28th and I finally was awarded the badge.

I woke up this morning and had my badge, I didn’t do any yoga yesterday so maybe that means they fixed whatever was wrong. I had a friend who hasn’t done yoga in a year and she got it a few days ago. Hahaha, there was clearly an issue.

I have over 10 Yoga session since May 1. However, these are all manual adds. How does one change the activity list to include Yoga? I have a VivoSport.

Manual activities do not work for badges. Have a look at you user manual here and select the "Other" activity type when recording a yoga session. Change the type then to Yoga in Garmin Connect.