never had this problem of new resources not appearing on iPad before..
Is this newly released, or simply newly purchased.? If the former, it may take a period of time before the resource is released for mobile. You may also need to update your mobile software.
This thread will be moved to the mobile forum for iOS
There was one recently-released resource that wasn't being made available in mobile apps for some reason or another, but I can't remember if this was it. A quick search of the iPad forum will find it.
Please see https://www.logos.com/product/30296/institutes-of-elenctic-theology . This resource is not available on mobile.