Concurrent Program with output defined as xls not getting extension in Edge

We are on Oracle EBS 12.2.10. Discovered recently that certain types of Excel reports aren't opening in Edge or Chrome, because they aren't getting the file extension on the file. The report appears in the download window, but no file extension, so if you click on it, it won't open. You had to add the extension in the download folder then it will open. This used to work before and it does still work in Firefox. The report is generated via PL/SQL and written using fnd.output. The concurrent program has xls defined as output.