diff --git a/src/interfaces/libpq/fe-auth-scram.c b/src/interfaces/libpq/fe-auth-scram.c
index 97db0b1faa..7ef5cc437e 100644
--- a/src/interfaces/libpq/fe-auth-scram.c
+++ b/src/interfaces/libpq/fe-auth-scram.c
@@ -437,6 +437,8 @@ build_client_final_message(fe_scram_state *state, PQExpBuffer errormessage)
 	/*
 	 * Construct client-final-message-without-proof.  We need to remember it
 	 * for verifying the server proof in the final step of authentication.
+	 * This needs to be kept consistent with the cbind_flag handling when
+	 * building the first client message in build_client_first_message().
 	 */
 	if (strcmp(state->sasl_mechanism, SCRAM_SHA256_PLUS_NAME) == 0)
 	{