diff --git a/docs/solutions/integration-issues/stale-grav-version-blocks-api-plugin-install.md b/docs/solutions/integration-issues/stale-grav-version-blocks-api-plugin-install.md
index 231bd18..abd6989 100644
--- a/docs/solutions/integration-issues/stale-grav-version-blocks-api-plugin-install.md
+++ b/docs/solutions/integration-issues/stale-grav-version-blocks-api-plugin-install.md
@@ -81,7 +81,7 @@ GPM (Grav Package Manager) only offers a plugin version whose declared Grav requ
 
 - **Keep `.env.<env>` `GRAV_VERSION` current.** It is the version a *fresh* `make remote-install-<env>` bakes in; a stale value silently installs an old core. After any core upgrade, bump the env file too — self-upgrade only moves the running server. Note this is a *third* version-authority surface alongside `user/config/system.yaml` `gpm.releases` (channel) and `plugins.txt` — they must stay in sync.
 - **When GPM says "package not found" for a package you know is on your channel, check the target's Grav core version first** (`php bin/grav --version` on the server, or `make remote-diag-<env>`). GPM filters by core compatibility; "not found" often means "no version compatible with your core," not "missing from the index." `gpm index -f` will not help.
-- **Don't trust a top-level install "Success" to mean dependencies installed.** A fresh install can leave a plugin's declared dependency unsatisfied (here `admin2` installed but its `api` dependency didn't). Verify with `ls user/plugins/<dependency>`.
+- **Don't trust a top-level install "Success" to mean dependencies installed.** A fresh install can leave a plugin's declared dependency unsatisfied (here `admin2` installed but its `api` dependency didn't). Verify with `ls user/plugins/<dependency>`. The same `ls` guards a *second*, distinct way a plugin ends up non-functional: its **code folder can be missing while its config persists** (e.g. in the per-host env tree), so it looks configured but never loads. Checking `ls user/plugins/<name>` catches both the missing-dependency and the config-without-code cases — see `grav-plugin-config-without-code-wont-enable.md`.
 - **Know the Admin2 ⇄ api coupling.** Admin2 authenticates via the api plugin's `/api/v1` endpoints; a missing or unrouted api plugin makes admin login fail *silently* (login POST 404s, nothing logged). A quick `curl /api/v1/pages` expecting `401` (not `404`) is a good post-deploy smoke check.
 
 ## Related
@@ -92,3 +92,7 @@ This is one of three independent gotchas from the same **2026-07-04 Grav 2.0.4 p
 - `docs/solutions/test-failures/new-user-grants-api-not-admin-on-admin2.md` — sibling: an authenticated account is denied an admin-gated page because `login new-user` auto-detect granted `api.*` but not `admin.*`. Different root cause (permission provisioning), same admin2/api area.
 - `docs/working/plans/2026-07-04-grav-2.0.4-upgrade.md` — the upgrade plan whose Global Constraints spell out the GPM version floors (`grav >=2.0.4`, `api >=1.0.6`) that cause the "package not found" on an rc core.
 - `docs/solutions/conventions/grav-plugin-config-must-be-tracked-override.md` — the *other* latent problem from this same investigation: the api plugin's functional config (`enabled` / `route` / `session_enabled`) must live in the tracked `user/config/plugins/api.yaml` to deploy at all. Necessary but not sufficient here (the plugin must be installed first), but a durable convention in its own right.
+
+A closely-related **sibling in the "plugin absent/non-functional on prod" family** (from the 2026-07-05 follow-up, not one of the three cutover gotchas above):
+
+- `docs/solutions/integration-issues/grav-plugin-config-without-code-wont-enable.md` — same outcome (a plugin inert on prod, fixed by a GPM install + cache clear), **different trigger**: there, GPM won't *offer* the plugin because the core is below the version floor; there, the plugin's *code folder is simply missing* while its config persists in the env tree (config-without-code desync). Same `ls user/plugins/<name>` smoke check flushes both out.