diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2baf067e9..271fde730 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,7 +12,7 @@
 
 ### Fixed
 - **`lib/redact-patterns.ts` `isCiRunIdentifier`**: an 11-digit GitHub Actions run id right after a run word on the same line (`screen 40477638211 GREEN`, `gate=…`, `rerun passed …`, `run #…`) is not `pii.phone.e164`, in every scanner (`gstack-approvals add`, `gstack-decision-trail`, the pregate secrets check, `gstack-post`); the run-word regex moved there from `lib/gstack-post.ts`, which imports it for its chained-id allowlist. A 10-digit national number after a run word, a bare 11-digit number, an E.164 `+` number and `job`, `id`, `workflow` or `attempt` before one still report; a national number written without its `+` right after a run word reads as a run id, the accepted residual of the ruling that a run id is not a phone number (`gstack-post` has read it that way since GSTA-121).
-- **`scripts/ubicloud/ubi-runner.sh pack`**: the live `.git` is never tarred. The refs are fetched into a fresh repository through git's transport (`--update-shallow`, so a shallow CI or Capy checkout packs), the `remote.*` and `branch.*` config is replayed so `origin/<base>` and each branch's upstream resolve on the VM, a detached HEAD gets a `detached-<sha12>` branch, the index is copied as before, and a pack that fails removes its temporary repository; a review subagent's `git diff` or a trial merge's `worktree add` during the first minute of a remote gate no longer makes tar exit 1 (`PREGATE_REMOTE_INFRA`). The linked-worktree path uses the same snapshot.
+- **`scripts/ubicloud/ubi-runner.sh pack`**: the live `.git` is never tarred. The refs are fetched into a fresh repository through git's transport (`--update-shallow`, so a shallow CI or Capy checkout packs), the `remote.*` and `branch.*` config is replayed so `origin/<base>` and each branch's upstream resolve on the VM, a detached HEAD gets a `detached-<sha12>` branch, the index is copied with the blobs staged against HEAD (a VM `gstack-wtree` can read a staged file), and a pack that fails removes its temporary repository; a review subagent's `git diff` or a trial merge's `worktree add` during the first minute of a remote gate no longer makes tar exit 1 (`PREGATE_REMOTE_INFRA`). The linked-worktree path uses the same snapshot.
 - **`lib/pregate/import-graph.ts`**: a relative string literal (`'../ship/sections/pr-body.md.tmpl'` through `new URL(…, import.meta.url)` or `readFileSync`) is a dependency edge from the file that names it, like a relative import; `test/ship-publication-gates.test.ts` is now selected when the pr-body template changes (the remote free gate missed it in GSTA-121's ship). A literal that climbs out of the repository names nothing.
 - **`scripts/lib/windows-curation.ts`**: `test/pregate-remote-stamp-only.test.ts` is `KNOWN_WINDOWS_INCOMPATIBLE` (it expects the Linux-host lanes verdict and skips itself on win32), as #3485's follow-up asked.
 
diff --git a/scripts/ubicloud/ubi-runner.sh b/scripts/ubicloud/ubi-runner.sh
index 1a65a629e..4f0fba5f5 100755
--- a/scripts/ubicloud/ubi-runner.sh
+++ b/scripts/ubicloud/ubi-runner.sh
@@ -626,15 +626,19 @@ cmd_pack() {
       git -C "$tmp/.git" config --add "${entry%%$'\n'*}" "${entry#*$'\n'}"
     done < <(git -C "$gitdir" config --local --null --get-regexp '^(remote|branch)\.' 2>/dev/null || true)
     # The checkout's index rides along so the VM's status matches, except a
-    # split index, whose shared half lives only in the original git dir. Its
-    # staged blobs are not behind any ref, so they travel as a pack of their
-    # own; without them the VM's write-tree (gstack-wtree) cannot read a
+    # split index, whose shared half lives only in the original git dir. The
+    # blobs staged against HEAD are behind no ref, so they travel as a pack of
+    # their own; without them the VM's write-tree (gstack-wtree) cannot read a
     # staged file.
     if [ "$(git -C "$src" config --bool core.splitIndex 2>/dev/null)" != true ]; then
       cp "$(cd "$src" && cd "$(dirname "$(git rev-parse --git-path index)")" && pwd)/index" "$tmp/.git/index"
-      git -C "$src" ls-files -s | awk '{print $2}' | sort -u \
-        | git -C "$src" pack-objects -q --stdout 2>/dev/null \
-        | git -C "$tmp/.git" unpack-objects -q
+      # Read the copy, not the live index, so the pack matches it; a gitlink's
+      # sha (mode 160000) is a submodule commit this object store lacks.
+      GIT_INDEX_FILE="$tmp/.git/index" git -C "$src" diff --cached --raw --no-abbrev HEAD \
+        | awk '$2 != "160000" && $4 !~ /^0+$/ {print $4}' \
+        | git -C "$src" pack-objects -q --stdout \
+        | git -C "$tmp/.git" unpack-objects -q \
+        || die "pack: could not snapshot the staged blobs of $src"
     fi
     (
       cd "$src"
diff --git a/test/ubicloud-runner.test.ts b/test/ubicloud-runner.test.ts
index a4ee26692..6122d0bc9 100644
--- a/test/ubicloud-runner.test.ts
+++ b/test/ubicloud-runner.test.ts
@@ -340,9 +340,11 @@ test('pack ships a linked worktree with a self-contained .git on the checked-out
       const broken = Bun.spawnSync(['bash', '-c', `rm -f .git/index && TMPDIR=../tmpd ${pack} > ../pack-broken.tgz; echo rc=$?; ls ../tmpd`], { cwd: src, timeout: 60_000 });
       expect(broken.stderr.toString()).toContain('.git/index');
       expect(broken.stdout.toString().trim()).toBe('rc=1');
-      sh('git reset -q', src);
+      // A gitlink in the index (a submodule commit this object store lacks) is not packed, and a valueless
+      // remote key (`[remote "origin"] mirror`) replays as true.
+      sh('git reset -q && git update-index --add --cacheinfo 160000,1111111111111111111111111111111111111111,sub && printf \'[remote "origin"]\\n\\tmirror\\n\' >> .git/config', src);
       sh('mkdir vm2 && ' + pack.replace('pack .', 'pack src') + ' | tar -xzf - -C vm2', d);
-      expect(sh('git rev-parse --abbrev-ref @{u}', join(d, 'vm2')).trim()).toBe('origin/main');
+      expect(sh('git rev-parse --abbrev-ref @{u} && git config --bool --get remote.origin.mirror && git ls-files -s sub | cut -c1-6', join(d, 'vm2')).split('\n').filter(Boolean)).toEqual(['origin/main', 'true', '160000']);
     } finally { rmSync(d, { recursive: true, force: true }); }
   }, 90_000);