Schema change SourceRecords have null partition

I noticed that the "my_connect_offsets" topic has two entries for the Debezium Oracle connector

["oracle-logminer-connector",null]    {"snapshot":true,"scn":"7898027","snapshot_completed":false}
["oracle-logminer-connector",{"server":"oracle-test"}]    {"commit_scn":null,"transaction_id":null,"scn":"7903065"}

where I would have expected only one.

Scanning through the code, it looks like the one with the null partition is emitted in EventDispatcher.java:schemaChangeEvent().

Why is it correct to not use the usual partition there? I don't see a place where this offset is read?