She did buck a small bit while I warmed her up on the ground. I'm sure the rear cinch felt constraining as she hasn't felt a rear cinch in months. However, it was short lived and we were warming up nicely after the first few minutes.
Once I hopped on, I took it slow to be sure she was calm and thinking. After about 10 minutes I realized she was fine and we went to work. We did large circles (25m) and changed direction through x repeatedly. I did not canter her tonight as I decided not to push with me in the western for the first time. It was a good, good session and she felt very balanced.
After our time in the arena, I rode her out to the play yard. This is her first time leaving the arena with a rider on her back. We weaved through trees, stood on the obstacles, played with backing up a bit and just relaxed. It was fascinating to me that she blew and blew when we were on the playground out of the arena. I'm guessing it's because we were closer to the herd, but she was happy to be there and remained responsive. What a great girl she was!
I got her trimmed after riding and her hooves are shaping nicely and amazingly hard. I hope she stays barefoot for life - she's got the feet for it.