Today 11:25 AMLatveria
Haven't heard any info for TM previews. It was probably the ride staff getting a ride through which is common to happen before the rest of the TM's get there preview.
I don't think this was the case. It sounded like the the TM's were split half worked while the other half enjoyed. Then they swapped. Sounded like it pretty much fully operational even to include 3 broomsticks and the shops. All this was posted by Dax on the site.