Yup, one of those screen is the Homescreen and the other is the (Inside-a-)Collection screen, which, for all intents and purposes, and as weird as it may sound, are two different beasts altogether (see how, inside the collection, you're not filtering by "Docs", but sorting by "Title"? Although mostly irrelevant to your puzzlement, it proves that they behave differently).
As far as I can see, everything is behaving properly, and what happened yesterday is just that you had *ONE* file in that collection 'tagged' (more accurately, with the cdeType set to) PDOC, while the others were in fact EBOK.
That one PDOC most likely made the collection appear as *containing* (but not *completely composed of*) PDOCs by the filter "Docs" (that, or the "Docs" filter doesn't care at all about collections, and you see collections anyway, no matter what they contain: you can answer that by telling me if you happen to have other collections on your device
).
And yeah, a file with a PDOC cdeType automatically gains an unsightly "Personal" banner on FW 5.X.
If you want to replicate the behaviour of your first screenshots, just put a bogus PDOC book in the same collection as a bunch of EBOK books.