There's some additional weirdness where I've booked the TATL segment in isolation (e.g., FCO-JFK or JFK-LHR) and then trying to add on the domestic segment (e.g., JFK-SFO or BOS-JFK) will replace the entire PNR with the domestic segment only, but still at the 57.5k TATL rate, and then the booking is not viewable from the AS UI. Cancelling such an award refunded me my taxes, but I still need to call in to get my miles back as it's been over a week.