Just upgraded to version 3.1.5. Great customizable theme that looks great but had a problem with drop down menu only showing fleetingly on mobile.
The following steps fixed it:
Step 1: WPTouch/Core Settings/Admin Mode/Advanced/Save
Step 2: WPTouch/Core Settings/Tools & Debug/Use JQuery 2.0 in themes/ Save
I only saw the option to use JQuery 2.0 AFTER saving at the end of Step 1.