The recent files plugin returns non-existent files as results and throws out an error when selecting such a result. Ideally, non-existent files would not be shown. Another solution would be to remove non-existent files from search results after being selected once and the error shown notifying the user the file no longer exists.
Thank you for the bug report! Please note that Plasma 5.25.5 is not supported for much longer by KDE; supported versions are 5.24, and 5.26 or newer. If at all possible please upgrade to a supported version and verify that the bug is still happening there.
Can confirm on Plasma 5.26.
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-workspace/-/merge_requests/2233
Related: https://bugs.kde.org/show_bug.cgi?id=410017