diff --git a/bundled-addons/aegis/lib/tron-decode.js b/bundled-addons/aegis/lib/tron-decode.js
index 8ecc60ae..396fc3b9 100644
--- a/bundled-addons/aegis/lib/tron-decode.js
+++ b/bundled-addons/aegis/lib/tron-decode.js
@@ -81,9 +81,20 @@ module.exports = function makeTronDecode({ sha256, base58check }) {
     }
     return out;
   }
-  const one = (fields, n) => fields.find((f) => f.field === n);
-  const bytesOf = (fields, n) => { const f = one(fields, n); return f && f.wire === 2 ? f.value : null; };
-  const numOf = (fields, n) => { const f = one(fields, n); return f && f.wire === 0 ? f.value : null; };
+  // A singular field that appears twice is legal protobuf: the parser keeps
+  // the LAST copy (and merges repeated sub-messages). java-tron does that, so
+  // reading the first copy would show the user one recipient and amount while
+  // the chain executes another — and Any.value is opaque bytes, so the signed
+  // hash is the same either way. Refuse instead of guessing, and refuse a
+  // known field sent with the wrong wire type for the same reason.
+  const one = (fields, n, wire) => {
+    const hits = fields.filter((f) => f.field === n);
+    if (hits.length > 1) throw new Error(`field ${n} appears ${hits.length} times; refusing an ambiguous transaction`);
+    if (hits[0] && hits[0].wire !== wire) throw new Error(`field ${n} has wire type ${hits[0].wire}, expected ${wire}`);
+    return hits[0];
+  };
+  const bytesOf = (fields, n) => { const f = one(fields, n, 2); return f ? f.value : null; };
+  const numOf = (fields, n) => { const f = one(fields, n, 0); return f ? f.value : null; };
 
   // 21-byte Tron address (0x41 || h20) → "T…" base58check. Anything else is
   // returned as hex so the overlay never hides a malformed field.