Hi everyone, I'm wondering if anybody has experienced this error before and worked out how to fix it?

I've logged an entry for business meals with attendees, all info is filled out (including all attendees), receipt it attached however the 'Enter Vendor Name' field is pre-populated with 'No Vendor Supplied' and I'm unable to change it. This error is preventing me submitting the report and I can't work out how to fix it.