I have not updated to IOS7 on my iPad 3 as I heard of problems with bad loading.
However last week I bought an iPad Air and the damned thing has both problems with tiles not loading and also crashes much more than my iPad 3 with IOS6.
However it seems to work very different depending on maybe the Krpano version or some other differences.
I just made a gallery using last version for a client and got constant missing tiles on all panos which loads immediately when you touch the pano.
This has 1024 and 2048 cubefaces in 512 tiles
http://www.360-foto.dk/dnm-alle/
On the iPad 3 there is no problem.
The missing tiles I see on this tour http://www.360-foto.dk/danmark-og-zarernes-rusland is different. It´s using last version from december and it is also using the old file structure and has 4 levels from 512 to 4096.
Hans