diff --git a/mining/errors/src/mempool.rs b/mining/errors/src/mempool.rs
index 43bf4a5119..132f7e2fd7 100644
--- a/mining/errors/src/mempool.rs
+++ b/mining/errors/src/mempool.rs
@@ -82,7 +82,7 @@ pub enum RuleError {
     #[error("Rejected tx {0} from mempool due to incomputable storage mass")]
     RejectStorageMassIncomputable(TransactionId),
 
-    #[error("Rejected RBF tx {0} from the mempool for having an unreasonably high fee of {1} sompi, indicating a possible user error. Use fee <= 50 KAS, or increase over previous feerate by 2x at most.")]
+    #[error("(PNN only) Rejected RBF tx {0} from the mempool for having an unreasonably high fee of {1} sompi, indicating a possible user error. Use fee <= 50 KAS, or increase over previous feerate by 2x at most.")]
     RejectRbfUserError(TransactionId, u64),
 }
 
diff --git a/mining/src/mempool/replace_by_fee.rs b/mining/src/mempool/replace_by_fee.rs
index 257a079816..1650035e74 100644
--- a/mining/src/mempool/replace_by_fee.rs
+++ b/mining/src/mempool/replace_by_fee.rs
@@ -8,6 +8,7 @@ use kaspa_consensus_core::{
     constants::SOMPI_PER_KASPA,
     tx::{MutableTransaction, Transaction},
 };
+use kaspa_core::warn;
 use std::sync::Arc;
 
 impl Mempool {
@@ -165,7 +166,9 @@ impl Mempool {
         {
             if transaction_feerate > double_spend_feerate {
                 if transaction.calculated_fee.unwrap() > SOMPI_PER_KASPA * 50 && transaction_feerate > double_spend_feerate * 2.0 {
-                    return Err(RuleError::RejectRbfUserError(transaction.id(), transaction.calculated_fee.unwrap()));
+                    let err = RuleError::RejectRbfUserError(transaction.id(), transaction.calculated_fee.unwrap());
+                    warn!("Mempool RBF high fee guard: {err} ({}, {})", transaction_feerate, double_spend_feerate);
+                    return Err(err);
                 }
                 return Ok(owner);
             } else {