When a Copyholder is attached to an Editor in Outliner view, attempting to execute Text Find always invokes the Outliner Filter, even when the Copyholder has focus.
This is true for keyboard shortcuts or menu options.
See the screenshot below. The Copyholder has focus, but the menu option is forcing Outliner Filter, not Text Find.
Note in the screenshot that the Find Next / Find Previous commands will work, if a prior Text Find has been done.
This seems to be similar to an issue I reported last year where the Outliner Filter overrode Text Find in QRPs, which has since been fixed. (You can tell I use the Outliner a lot!)