If you have ever scrolled a catalogue and spotted "(Rerecorded)" or "(Re-recorded)" after a song title, here is what we take it to mean. The label marks a newly made recording of a song the artist has already released. The song is the same, but the recording is not: it is a fresh performance captured again, and the bracket after the title is there to say so.
A re-recording is a separate recording, so it appears as its own entry and does not replace the original. Both can sit in a catalogue at the same time, and the label in brackets is usually what tells them apart. Sometimes a batch arrives together, with several catalogue songs posted at once. That pattern suggests a catalogue project rather than a single new release, although the posts themselves do not usually spell out the reason.
Why does it happen? Reasons vary, and a post usually does not say which one applies. Some neutral possibilities are a lineup that has changed since the original, a catalogue being made available in a new form, an anniversary or reissue project, or a rights and licensing arrangement that makes a fresh recording the practical route. Without an official statement, a listener cannot tell which reason is behind any given release, and guessing is not worth doing.
In practice, streaming and view counts start over on the new entry, so the numbers on a re-recording are not comparable with the numbers on the original. If you are looking for the version you remember, check the bracket before you press play, because a playlist can end up holding one in place of the other. One limit is worth stating plainly: a re-recording is not a remaster. A remaster reworks the existing recording, while a re-recording is performed again from scratch. The labels are different, and so is the thing you are listening to.