Look through your versions and find the one where you had the link to the file that was deleted
The preview should load with the following error
SilverStripe\View\Parsers\ShortcodeParser::replaceAttributeTagsWithContent(): unterminated entity reference stage=Stage
GET /YOUR_PAGE/?stage=Stage&archiveDate=2021-08-18%2019%3A58%3A11
Line 478 in /Users/.../vendor/silverstripe/framework/src/View/Parsers/ShortcodeParser.php
Note that the error is only reported all the way back up at ShortcodeParser - replaceAttributeTagsWithContent.
The following is triggering a warning when trying to parse a not found file and the error page is loaded instead. This seems to be caused because the returned Link is not parsed. https://github.com/silverstripe/silverstripe-assets/blob/ce9464b6282c34e37324987ea2dd74cae89c50ca/src/Shortcodes/FileShortcodeProvider.php#L102
Steps to reproduce
Note that the error is only reported all the way back up at
ShortcodeParser - replaceAttributeTagsWithContent
.