diff --git a/scripts/verify-aiui-deploy.sh b/scripts/verify-aiui-deploy.sh
index 11476d32..e0204209 100755
--- a/scripts/verify-aiui-deploy.sh
+++ b/scripts/verify-aiui-deploy.sh
@@ -63,11 +63,17 @@ echo "$(timestamp) Resolved ${#LIVE_PATHS[@]} live chunk(s) from the precache ma
 
 FOUND=0
 CHECKED=0
+# Fetch to a temp file and grep that, NOT `curl | grep -q`: under this
+# script's pipefail, grep -q's early exit EPIPEs curl (exit 23) whenever
+# the marker sits before the tail of a >64KB chunk, turning a genuine
+# match into a nondeterministic FAIL.
+BODY_TMP="$(mktemp)"
+trap 'rm -f "$BODY_TMP"' EXIT
 for path in "${LIVE_PATHS[@]}"; do
     [ -z "$path" ] && continue
     CHECKED=$((CHECKED + 1))
     url="${BASE}/aiui/${path}"
-    if curl -sf -m 15 "$url" 2>/dev/null | grep -q -- "$MARKER"; then
+    if curl -sf -m 15 -o "$BODY_TMP" "$url" 2>/dev/null && grep -q -- "$MARKER" "$BODY_TMP"; then
         echo "$(timestamp)   MATCH: $path"
         FOUND=1
         break