X_DOC_CHANGELOG_SECTION_INVALID

a CHANGELOG.md section is not one section

two ## headings name the same version, or a released section has no body. scripts/release.ts raises the same code for the third shape, refusing before a manifest is written: an [Unreleased] with no body and no commit since the previous tag would ship a version section that says nothing. A fourth sits under the same code in scripts/changelog-check.ts: a released section whose body is the auto-generated ### Commits block alone — what promoteUnreleased appends when [Unreleased] held no human-written notes — so the release it names shipped no release notes of its own ([Unreleased] itself is exempt: its notes are simply not written yet). The release script used to append a section generated from commit subjects instead of promoting [Unreleased], and that is what put two ## 5.0.1 headings and two ## 5.0.0 headings in the file — a dateless generated one above the hand-written one, each time. Both pairs sat there from the release: 5.0.1 commit until release: 6.0.0 merged them by hand

merge the two sections into one, or delete the generated one, then bun run scripts/changelog-check.ts --json — it names the line. For the empty case, write the notes under ## [Unreleased] in CHANGELOG.md and run the release again. For the commits-only case, write the human-written release notes for the version the cause names under its heading in CHANGELOG.md, above the ### Commits block, then bun run scripts/changelog-check.ts --json