diff --git a/lightningd/notification.c b/lightningd/notification.c
index 450ce0a06..d2f8ca49d 100644
--- a/lightningd/notification.c
+++ b/lightningd/notification.c
@@ -191,8 +191,9 @@ static void forward_event_notification_serialize(struct json_stream *stream,
 		cur->channel_out = *scid_out;
 		if (amount_out) {
 			cur->msat_out = *amount_out;
-			assert(amount_msat_sub(&cur->fee,
-					       in->msat, *amount_out));
+			if (!amount_msat_sub(&cur->fee,
+					     in->msat, *amount_out))
+				abort();
 		} else {
 			cur->msat_out = AMOUNT_MSAT(0);
 			cur->fee = AMOUNT_MSAT(0);
diff --git a/openingd/openingd.c b/openingd/openingd.c
index b7fb61b97..c392b25d3 100644
--- a/openingd/openingd.c
+++ b/openingd/openingd.c
@@ -852,7 +852,13 @@ static u8 *funder_channel_complete(struct state *state)
 
 	/* We recalculate the local_msat from cached values; should
 	 * succeed because we checked it earlier */
-	assert(amount_sat_sub_msat(&local_msat, state->funding, state->push_msat));
+	if (!amount_sat_sub_msat(&local_msat, state->funding, state->push_msat))
+		status_failed(STATUS_FAIL_INTERNAL_ERROR,
+			      "push_msat %s > funding %s?",
+			      type_to_string(tmpctx, struct amount_msat,
+					     &state->push_msat),
+			      type_to_string(tmpctx, struct amount_sat,
+					     &state->funding));
 
 	if (!funder_finalize_channel_setup(state, local_msat, &sig, &tx))
 		return NULL;