diff --git a/docs/ISSUES.md b/docs/ISSUES.md
index 9fb720a9..83151052 100644
--- a/docs/ISSUES.md
+++ b/docs/ISSUES.md
@@ -24,6 +24,20 @@ What does NOT go here:
 - Every session: scan OPEN issues at start; promote/close anything we touched during the session before ending.
 - Promoting to a Phase: mark as `DONE (promoted to Phase X)` + commit SHA where the Phase entry landed.
 
+## #392 — A refused/failed fullscreen enter leaves `fullscreen: true` persisted against a windowed client
+
+**Status:** OPEN — filed 2026-08-13 from the #376/#388 blast review (M4).
+The save path persists the Full Screen flag BEFORE the apply runs; when
+the state-aware apply then refuses (mode not offered / catalog absent) or
+the native switch fails, the client stays windowed while settings.json and
+the Config checkbox keep saying fullscreen — a silent flag/reality
+divergence that survives restarts (it re-creates #377's stuck-flag
+recovery shape, minus the crash). The proper fix is an apply-result seam:
+`IRuntimeDisplayWindowTarget.Apply` reports what actually took effect and
+`RuntimeSettingsController` reconciles the stored `DisplaySettings` —
+NOT a store write-back from inside the target (layering). Small,
+self-contained; part of the display block's tail.
+
 ## #391 — Resolution list: offer only modern modes from the monitor's real mode list (user-directed curation)
 
 **Status:** DONE 2026-08-13 (this commit) — display block slice 2, pending