When importing CSV (migrating from Scarab) to Jira, I'm 95% successful but it complains about two of the Comment author names not being Jira users, therefore assigning the authors to myself.
The names are similar to two actual users, but without space between Firstname Lastname.
e.g. CSV Comment entry "05/01/2021 14:00; John Smith; blah blah blah"
is not accepted and Jira complains about johnsmith being unknown
The names rejected do not actually exist anywhere in the CSV from a simple search.