diff --git a/docs/pfi/fleet-conventions.md b/docs/pfi/fleet-conventions.md
index 580a9a0..3126494 100644
--- a/docs/pfi/fleet-conventions.md
+++ b/docs/pfi/fleet-conventions.md
@@ -155,6 +155,19 @@ The setgid bit on directories is load-bearing: it makes every file created
 afterwards inherit the `docker` group, so the scheme does not decay back into
 whoever-touched-it-last ownership.
 
+⚠ **A stack dir that is a git checkout needs `safe.directory` for its deploy
+user.** git (>= 2.35.2) refuses to operate in a worktree whose top-level dir is
+owned by someone else, so moving a checkout to `root:docker` breaks any deploy
+that runs `git fetch`/`reset` as a normal user, with `fatal: detected dubious
+ownership`. That's what stalled yt-voice-clipper's webhook auto-deploy on irv-ml1
+after the 2026-09-14 normalization, found 2026-09-24 when v0.3.13 would not
+land. The fix keeps the convention: as the deploy user,
+`git config --global --add safe.directory /opt/docker/compose/<stack>` (one
+entry per repo; the `/*` wildcard form needs git >= 2.46, and irv-ml1 has
+2.39). Swept 2026-09-24: that was the only checkout under a normalized
+`/opt/docker/compose` deployed by a non-root user. esh-docker-vm's
+`/opt/docker/conf/esphome/` is a checkout but is `root:root` throughout.
+
 ⚠ **A stack lives under `/opt/docker/compose/<stack>/` or it is invisible.**
 Every piece of fleet automation walks that path. `talk` sat at `~/talk` until
 2026-09-14 and was silently skipped by the docker-ce upgrade's restart loop for