I've seen this reported both from Brooklyn, before the 3.4.0 build, and from Santa Clara, after the 3.4.0 build but not confirmed to be that build as of yet.

Description from Santa Clara patron:

"Initially the app worked fine on both my iPhone and iPad, and then, suddenly, it lost all memory of my account on both devices. When I went into the app it couldn’t find the catalog and I could not trigger it to ask me to set my library again

So, I deleted the app, re-downloaded it from the App Store and set up my library and account. This lasted about 2 days and then it zeroed out again and lost my account and library

I did this for about a week with both devices."

Currently asking for version of app and platform.