Well.... 2.5 weeks since last post in this thread. Flights are still showing the PS seat map, and the F only booking class seems to have resolved. The flight we are booked on started showing Y seats available and went F7 R1 couple days ago. Yesterday it went F7 R3, and I decided to jump on those three upgrades. Now F6 R0, which seems a bit odd.
All the flights with the PS bird are #391 as best I can tell. Maybe they are taking a regular 757-200 out for maintenance, and subbing in a spare PS bird? One can hope...