I carry out updates almost every week. In the last couple of months I found that a few of the resources I bought did not appear in the library when I searched for keywords in the title.
Recently, I was sure I was missing something and searched for more keywords, and voila the missing resources appear in the library. When I click to open a resource, a message appears to say that this title is "not on your device" or something, and gives me the option to manually download the resource, which I now do and the resource shows up normally.
What's the point of this new procedure? It is very frustrating.