If you have a bad leader in your MARCXML, trying to generate USMARC from it can itself throw a fatal error: my $usmarc_record = $record->as_usmarc(); substr outside of string at /usr/share/perl5/MARC/Record.pm line 570. Something went wrong rebuilding indexes for kohadev
Renaming from '$record->as_usmarc() throws fatal errors for bad leaders' because there's actually a lot of places where MARC::Record will throw fatal errors. For example '$record->encoding()'.