diff --git a/js/nostr/toolkit.js b/js/nostr/toolkit.js
index 94f46e5a..05d47e0b 100644
--- a/js/nostr/toolkit.js
+++ b/js/nostr/toolkit.js
@@ -151,7 +151,11 @@ function normalizeRelayList(relays) {
 // 64-char lowercase hex. A single malformed/odd-length entry makes strict relays
 // (e.g. primal) reject the whole REQ with "uneven size input to from_hex",
 // silently dropping that subscription's results.
-const HEX64_FILTER_FIELDS = ["ids", "authors", "#e", "#p", "#q"];
+// Includes the NIP-22 UPPERCASE root-scope tags #E (root event id) and #P (root
+// author pubkey) — relays hex-decode these too, and the kind-1111 comment
+// subscriptions query by them, so an odd-length value there was bypassing the
+// sanitizer and getting the whole REQ rejected with "uneven size input to from_hex".
+const HEX64_FILTER_FIELDS = ["ids", "authors", "#e", "#p", "#q", "#E", "#P"];
 const HEX64_PATTERN = /^[0-9a-f]{64}$/;
 
 // Strip invalid hex from the hex-only filter fields so one bad value can't get a
diff --git a/tests/filter-hex-sanitize.test.mjs b/tests/filter-hex-sanitize.test.mjs
index a3701af7..ab56bbe1 100644
--- a/tests/filter-hex-sanitize.test.mjs
+++ b/tests/filter-hex-sanitize.test.mjs
@@ -62,3 +62,20 @@ test("ignores empty/absent hex fields", () => {
   const out = sanitizeHexFilterFields({ kinds: [1], authors: [] });
   assert.deepEqual(out, { kinds: [1], authors: [] });
 });
+
+test("sanitizes NIP-22 uppercase root tags #E/#P (kind-1111 comments)", () => {
+  // Relays hex-decode #E (root event id) and #P (root author pubkey) too. An
+  // odd-length value there previously bypassed the sanitizer and got the whole
+  // comment REQ rejected ("uneven size input to from_hex").
+  const out = sanitizeHexFilterFields({
+    kinds: [1111],
+    "#E": [HEX_A, ODD],
+    "#P": [HEX_B],
+    "#K": ["30078"], // a non-hex tag must be left untouched
+    "#A": ["30078:" + HEX_A + ":dtag"], // address tag is not hex-decoded
+  });
+  assert.deepEqual(out["#E"], [HEX_A], "drops the odd-length root event id");
+  assert.deepEqual(out["#P"], [HEX_B]);
+  assert.deepEqual(out["#K"], ["30078"], "#K (kind) untouched");
+  assert.deepEqual(out["#A"], ["30078:" + HEX_A + ":dtag"], "#A (address) untouched");
+});
diff --git a/todo/TODO_2026-06-20_pre-launch.md b/todo/TODO_2026-06-20_pre-launch.md
index cd2b4375..a6dc2b03 100644
--- a/todo/TODO_2026-06-20_pre-launch.md
+++ b/todo/TODO_2026-06-20_pre-launch.md
@@ -233,9 +233,13 @@ un-hides when WebTorrent flips green). The real gaps:
       `loadCommunityBlacklistEntries` (admin editor/whitelist/blacklist lists? a
       per-author follow-set fetch?). Re-check on a fresh hard-refresh; if still ~32,
       trace the actual emitter.
-- [ ] **`from_hex` source not root-caused.** The sanitizer (`733cb593`) defends +
-      dev-logs `[toolkit] dropped N invalid hex value(s) from filter "<field>"` —
-      watch that log to find which subscription ships the odd-length hex, fix at source.
+- [x] **`from_hex` root-caused + FIXED (2026-06-23).** The sanitizer
+      (`HEX64_FILTER_FIELDS`, toolkit.js) covered `ids/authors/#e/#p/#q` but NOT the
+      NIP-22 UPPERCASE root tags `#E`/`#P`, which relays also hex-decode and which
+      the kind-1111 comment subscriptions (`commentEvents.js`) query by. An
+      odd-length root event-id/author there bypassed the sanitizer and got the whole
+      REQ rejected ("uneven size input to from_hex"). Added `#E`/`#P` to the
+      sanitized fields; test in `tests/filter-hex-sanitize.test.mjs`.
 - [x] **Relay `from_hex` REQ rejects fixed** (`733cb593`): one odd-length/non-hex
       value in `ids/authors/#e/#p/#q` made strict relays reject a whole REQ; now
       sanitized at the pool choke point (`normalizeFilterList`).