The problem is with a specific "Trainer sub-type" filter in the deck builder. Specifically, when you set the Trainer filter and also set the "Card Type" to "Trainer" (to see only the "basic" or "standard" Trainer cards), no cards are displayed. All the other Trainer Card Types are filtered properly.
Per my post in the RS support thread, it will be corrected in the next release, whenever that is...I'm not sure yet.