Good news. I was able to figure out that these sats we indeed migrated to a different wallet from an export/backup of that wallet on a different phone prior to the bluewallet sunset. What was seen on her bluewallet screen was out-of-date and did not reflect the transfer of sats to/from a restored wallet on a different phone. Whew. No sats lost.
However, that other wallet was lost in a tragic boating accident.
https://video.nostr.build/24e0e88209f5d99331b11c2f64b44bdcd4928dd0893ab3ec9928322f9d870374.mp4