Prior to the grant of Spider-Man (SPM) cards in place of Through the Omenpaths (OM1), I owned parallax/extended art styles for Viggo, Enforcer of Ig's Crossing (cognate to Eddie Brock) and Cren, Undercity Dreamer (cognate to Miles Morales). The collection interface now appears as though I do not own these styles, and curiously claims these styles cannot be purchased at this time (contrary to the behaviour of other OM1 styles).
Potentially relevant facts:

I owned these styles but did not own any copies of the cards.
These were the only two cards from OM1 I owned no copies of.
I had selected these styles as preemptive favourites despite not owning any copies of the cards.
My expectation, bolstered by discussions with WotC_Dave on the official Discord server, was that owning these styles alone would be sufficient to keep them with their original appearance post-grant. This has worked fine with all styles I owned for OM1 cards where I had copies of the cards. It is just these two that have gone missing.