When matching media to existing records the media importer attempts to rewrite file names to match identifiers on existing records. The rewriting is performed using regular expressions defined in the app.conf mediaFilenameToObjectIdnoRegexes directive.
In cases where identifiers include characters absent in the identifier portion of the file name (Eg. identifier is 2019.09.001 but file name is 201909001.jpg) rewriting of the file name cannot result in a match. In this case we'll need the ability to rewrite the identifiers for comparison purposes.