8.5.1 is great. Really great. Except when it decides to make your code no longer work. And especially when that code involves NotesView.GetDocumentByKey, NotesView.GetAllDocumentsByKey, NotesView.GetEntryByKey or NotesView.GetAllEntriesByKey...

Source: http://www.bleedyellow.com/blogs/erik/entry/8_5_1_fail_your_code_may_just_break19