We don't actually support Newstand as it is really just a 'wrapper' for other people's viewers. You need to use the Pocketmags viewer to be sure of it working on iOS.
View pocketmags on an iPad
All Newstand does is import the pocketmags app and try to display it, but a poke around on google suggests that it is not reliable with all third party formats.
If you keep getting problems and want to continue to use Newstand, I suggest contacting apple support or using their support forums.
Neil
Edited By Neil Wyatt on 13/09/2015 10:25:12