Hi David,
Could you please update us about the status of the situation? Are you investigating? Did you find anything that could cause this problem? Are you planning a theme update that resolves the problem?
Status for us:
We have a live site in which the problem exists.
We have a copy of the live site for development purposes on the same server and the problem does not exist.
It’s not a browser problem.
It’s not a server problem.
I think it has something to do with jQuery and caching.
I hope this helps and that you have a solution on a short notice.