For what it is worth, I just did a upgrade to 1.9.32 and the top navigation did not work at all in the mobile theme. Nothing displayed for page links, categories, tags or login.
I ran my site in Safari desktop in iPhone mode and ran the javascript debugger which provided error on “JQuery Colorbox” plugin… Ah, ha.. so
I checked and I was a upgrade behind on that plugin. Did the upgrade on Colorbox from 4.0 to 4.1 and WPTouch started working fine.