diff --git a/coins/monero/src/wallet/send/multisig.rs b/coins/monero/src/wallet/send/multisig.rs
index 18dba94b..4b7d0f69 100644
--- a/coins/monero/src/wallet/send/multisig.rs
+++ b/coins/monero/src/wallet/send/multisig.rs
@@ -175,13 +175,20 @@ impl StateMachine for TransactionMachine {
   fn sign(
     &mut self,
     mut commitments: HashMap<u16, Vec<u8>>,
-    // Drop FROST's 'msg' since we calculate the actual message in this function
-    _: &[u8]
+    msg: &[u8]
   ) -> Result<Vec<u8>, FrostError> {
     if self.state() != State::Preprocessed {
       Err(FrostError::InvalidSignTransition(State::Preprocessed, self.state()))?;
     }
 
+    if msg.len() != 0 {
+      Err(
+        FrostError::InternalError(
+          "message was passed to the TransactionMachine when it generates its own".to_string()
+        )
+      )?;
+    }
+
     // Add all commitments to the transcript for their entropy
     // While each CLSAG will do this as they need to for security, they have their own transcripts
     // cloned from this TX's initial premise's transcript. For our TX transcript to have the CLSAG