diff --git a/src/cjs/payments/p2ms.cjs b/src/cjs/payments/p2ms.cjs
index 9a40c7077..a7b1eacc5 100644
--- a/src/cjs/payments/p2ms.cjs
+++ b/src/cjs/payments/p2ms.cjs
@@ -90,7 +90,7 @@ function p2ms(a, opts) {
   function isAcceptableSignature(x) {
     return (
       bscript.isCanonicalScriptSignature(x) ||
-      (opts.allowIncomplete && x === OPS.OP_0) !== undefined
+      !!(opts.allowIncomplete && x === OPS.OP_0)
     );
   }
   v.parse(
diff --git a/src/esm/payments/p2ms.js b/src/esm/payments/p2ms.js
index 2d82e510e..58bc7a5fd 100644
--- a/src/esm/payments/p2ms.js
+++ b/src/esm/payments/p2ms.js
@@ -43,7 +43,7 @@ export function p2ms(a, opts) {
   function isAcceptableSignature(x) {
     return (
       bscript.isCanonicalScriptSignature(x) ||
-      (opts.allowIncomplete && x === OPS.OP_0) !== undefined
+      !!(opts.allowIncomplete && x === OPS.OP_0)
     );
   }
   v.parse(
diff --git a/test/fixtures/p2ms.json b/test/fixtures/p2ms.json
index fe9d0d6bb..586be3271 100644
--- a/test/fixtures/p2ms.json
+++ b/test/fixtures/p2ms.json
@@ -407,6 +407,17 @@
         "input": "OP_0 ffffffffffffffff"
       }
     },
+    {
+      "description": "Invalid signature rejected even with allowIncomplete",
+      "exception": "Input has invalid signature\\(s\\)",
+      "options": {
+        "allowIncomplete": true
+      },
+      "arguments": {
+        "output": "OP_1 030000000000000000000000000000000000000000000000000000000000000001 OP_1 OP_CHECKMULTISIG",
+        "input": "OP_0 ffffffffffffffff"
+      }
+    },
     {
       "description": "n > 20 (2-of-21 multisig)",
       "exception": "Output is invalid",
diff --git a/ts_src/payments/p2ms.ts b/ts_src/payments/p2ms.ts
index 862448a6a..a998237a9 100644
--- a/ts_src/payments/p2ms.ts
+++ b/ts_src/payments/p2ms.ts
@@ -47,7 +47,7 @@ export function p2ms(a: Payment, opts?: PaymentOpts): Payment {
   function isAcceptableSignature(x: Uint8Array | number): boolean {
     return (
       bscript.isCanonicalScriptSignature(x as Uint8Array) ||
-      (opts!.allowIncomplete && (x as number) === OPS.OP_0) !== undefined
+      !!(opts!.allowIncomplete && (x as number) === OPS.OP_0)
     );
   }