I did do a little experiment a few days ago to see if i could let my reviews show up on a 10 point scale instead of 5 point scale. I changed the rating value and added "bestRating" to the script. The testing tool showed no errors on this script. This could be related to this issue or could be pure coincidence.
I changed it back to its original state, we will what happens.
btw no other company in my niche is using review data. So we where unique in this.
And here a list of the agencies or google partners that are trusted bij Google. Thats what i meant bij third parties / agencies that are hosting reviews. I'm using one of them. When reaching the 150 reviews they should add review markup automaticly to my adwords campaigns also. btw they where not saying reviews markup is no longer used, they mentiod getting a lot of complaints lately of customers saying google didnt gave them they yellow stars in search results anymore.