Hi,
It is doe to a known issue with the latest release, where I was trying to fix another mobile related bug.
To resolve it, a small custom code snippet is needed. Place this code to the functions.php file in your active theme directory (copy from line 3):
(please make sure to have a full site back-up before making any changes to your site code!)
Let me know if you need help with implementing it.
I hope this helps!