In case the user chooses to reread EXIF, or in the case that an image is tried to be inserted a second time (e.g. because the regular KPA DB was not saved the first time), then an error is shown since we try to insert. In that case we should update instead. The code in question is in Exif::Database::insert
Is this closely related to https://bugs.kde.org/show_bug.cgi?id=207698 ?
and https://bugs.kde.org/show_bug.cgi?id=220372
Fixed in commit 9178127