diff --git a/actions/issueflow-reconcile/issueflow-reconcile.sh b/actions/issueflow-reconcile/issueflow-reconcile.sh
index cf7022a..fbe3d16 100644
--- a/actions/issueflow-reconcile/issueflow-reconcile.sh
+++ b/actions/issueflow-reconcile/issueflow-reconcile.sh
@@ -609,9 +609,22 @@ issue_payload_valid() { # $1 = the requested issue; payload on stdin
   # one catches an HTTP 200 whose body is `null`, which exits 0 and empties it
   # just the same. `.number` is checked against the issue asked for, so a
   # payload about some other issue can never be reconciled as this one.
+  # THE EMPTINESS CHECK IS NOT REDUNDANT, and it is not stylistic. `jq -e`
+  # disagrees with itself across versions on empty input: jq 1.7 exits 4 (no
+  # valid result was ever produced), jq 1.6 exits **0**. This instance's
+  # runner image (ghcr.io/catthehacker/ubuntu:act-22.04) carries jq 1.6, so
+  # without this line an EMPTY payload reads as a valid issue payload here —
+  # the precise thing D3 added this guard to refuse — and the sweep would
+  # reconcile an issue from a body it never received. Measured both ways,
+  # 2026-08-05: `jq -e '<this filter>' </dev/null` → rc 0 on 1.6, rc 4 on 1.7.
+  # The test that caught it is upstream's own and passes on a GitHub runner
+  # (#198).
+  local payload
+  payload="$(cat)"
+  case "$payload" in *[![:space:]]*) ;; *) return 1 ;; esac
   jq -e --arg n "$1" '
     type == "object" and (.number | tostring) == $n and (.labels | type) == "array"
-  ' >/dev/null 2>&1
+  ' <<<"$payload" >/dev/null 2>&1
 }
 
 skipped_tail() { # $1 = skip count, $2 = the issue numbers → the D6 line, or nothing
diff --git a/changelog.d/198.md b/changelog.d/198.md
index 5a58f55..e9f5f22 100644
--- a/changelog.d/198.md
+++ b/changelog.d/198.md
@@ -40,6 +40,11 @@
   speaks and refuses by name on a runner without it, instead of dying with
   `command not found` on every sweep. #205 ports it to REST (#198).
 
+- `issue_payload_valid` refuses an empty payload on jq 1.6 as well as 1.7.
+  `jq -e` exits 4 on empty input under 1.7 and **0** under 1.6, and this
+  instance's runner carries 1.6 — so the guard #247 D3 added to refuse an
+  unreadable read was accepting one here (#198).
+
 - The post-merge nudge strips a trailing slash from the server URL, so a forge
   URL carrying one does not render `//owner/repo` (#198).