Verify that the files belong together
First inspect the movie-version group and confirm that its entries are genuinely editions of one title. A similarly named but unrelated movie should not be repaired by simply selecting another default inside an incorrect group.
Check the installed release's policy
Kodi's wiki names Make the most recent version the default version in its v22 settings discussion; where available and enabled, it can promote a newly scanned edition. Match that guidance to the actual build, especially where the page labels a setting as a v22 change.
Record the preferred file and use the available manager control to make the default deliberate. Review any automatic new-version preference that exists in your release. A visible edition label is useful, but the acceptance check is which underlying file ordinary playback opens.
Preserve the result for the next scan
Keep a file-to-label inventory and review it after adding another edition. If the default changes again, compare the relevant setting and version before renaming files or discarding metadata. This keeps an ordinary playback preference separate from the identity of the title.
Questions answered
Are all setting labels on the current wiki present in v21?
No. The documentation includes later version changes; use the instructions applicable to the installed build.
Should I delete the new edition to preserve the old default?
First review the group and available default-selection policy. Preserve the original media while diagnosing it.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.