I have an ssis package that runs on a sql server 2016 instance without issue.
When run on a sql server 2022 instance it fails with the error:

Cannot convert between unicode and non-unicode

The package is reading data from a flatfile and loading it into a table.

The database is identical on both servers, database is backed up and restored immediately to the sql 2022 instance.
Collation is the same at instance, database and table levels.
The only difference I can see is the version of sql server.

Can anyone advise what might be happening here?