diff --git a/src/policy/fees.h b/src/policy/fees.h
--- a/src/policy/fees.h
+++ b/src/policy/fees.h
@@ -30,7 +30,10 @@
     /** Create new FeeFilterRounder */
     explicit FeeFilterRounder(const CFeeRate &minIncrementalFee);
 
-    /** Quantize a minimum fee for privacy purpose before broadcast **/
+    /**
+     * Quantize a minimum fee for privacy purpose before broadcast.
+     * Not thread-safe due to use of FastRandomContext
+     **/
     Amount round(const Amount currentMinFee);
 
 private: