I’m testing the theme Panda for PS 1.7.3 there is a problem with the ipad2 ios 9 when if enable the flag Smart cache for JavaScript ( true) the site doens’t work fine in the ipad2 while in the desktop and mobile is ok.
I guess the problem was caused by a 3rd party module you’ve installed. You can disable all 3rd party modules, and then enable them one by one to find it out.