Portable files exported before v1.39.1 carry no creation date for a
medication, so the restore stamped the restore time. The dose history reads
that date as the day the medication began to exist, and every miss before
it, including the day before the restore, dropped out of the record.
When the file has no creation date, the restore now uses the earliest thing
the file records for the medication: its first dose (scheduled, taken or
written), the start of its first schedule revision, its course start, its
first pause, dose change or side effect, and never a date after the restore.
A file that records nothing about the medication keeps the old default.