A probe against the live 0.16.19 says a one-off event comes back from an
expanded query as id "eaaaaai" with baseEventId "i" — an instance id of
its own, and a base that is a different event. The clause that treated a
differing base as an occurrence of a series would therefore have gone on
calling every event recurring, which was the bug.
So recurrence rules alone decide it. What that gives up is an expanded
instance that arrives without its rules attached; whether Stalwart does
that is still to be checked against a real series.
jcoffey-dev
330cecfb04