Thanks everyone for your thoughts. If nothing else, it’s nice to know we’re not the only ones that have had this issue. I’m happy to say that she seems to be doing fine, at least for now. My daughter continued to work with her using the same method you suggest, Joan. It would take about 3 times in and out and the mare would be fine. She has been moved to a new paddock with a new herd of mares and the barn manager reports she’s doing just fine. Now we just have to get her over the carrot habit that she developed with the gate training. : )
We seemed to have a bit of a break from the issues under saddle. We didn’t push her but over all she seemed more relaxed under saddle while they were having gate issues. Now that the gate issues seem to be gone, the anxiety under saddle is back.