Common reasons for a release to be superseded by a PROPER include:
: A fix released by the same group to correct their own mistake.
: Used in rare cases where a previous "PROPER" release was also found to be flawed and required its own correction. Why Releases Get "Propered"
In "scene" terminology, a tag indicates a corrected version of a release that fixes technical flaws or rules violations found in an earlier version by a different group.