diff --git a/lightningd/peer_control.c b/lightningd/peer_control.c
index 59e34dfa8..66db12e5f 100644
--- a/lightningd/peer_control.c
+++ b/lightningd/peer_control.c
@@ -1409,8 +1409,14 @@ static enum watch_result funding_spent(struct peer *peer,
 				  peer->funding_satoshi,
 				  &peer->channel_info->old_remote_per_commit,
 				  &peer->channel_info->remote_per_commit,
-				  peer->our_config.to_self_delay,
+				   /* BOLT #2:
+				    * `to_self_delay` is the number of blocks
+				    * that the other nodes to-self outputs
+				    * must be delayed */
+				   /* So, these are reversed: they specify ours,
+				    * we specify theirs. */
 				  peer->channel_info->their_config.to_self_delay,
+				  peer->our_config.to_self_delay,
 				  get_feerate(peer->ld->topology,
 					      FEERATE_NORMAL),
 				  peer->our_config.dust_limit_satoshis,
diff --git a/tests/test_lightningd.py b/tests/test_lightningd.py
index 50515648e..75b5e4cd8 100644
--- a/tests/test_lightningd.py
+++ b/tests/test_lightningd.py
@@ -791,7 +791,8 @@ class LightningDTests(BaseLightningDTests):
         # HTLC 1->2, 1 fails just after funding.
         disconnects = ['+WIRE_FUNDING_LOCKED', 'permfail']
         l1 = self.node_factory.get_node(disconnect=disconnects)
-        l2 = self.node_factory.get_node()
+        # Make locktime different, as we once had them reversed!
+        l2 = self.node_factory.get_node(options=['--locktime-blocks=10'])
 
         l1.rpc.connect(l2.info['id'], 'localhost', l2.info['port'])
 
@@ -814,8 +815,8 @@ class LightningDTests(BaseLightningDTests):
         l1.daemon.wait_for_log('-> ONCHAIND_OUR_UNILATERAL')
         l2.daemon.wait_for_log('-> ONCHAIND_THEIR_UNILATERAL')
 
-        # 6 later, l1 should collect its to-self payment.
-        bitcoind.generate_block(6)
+        # 10 later, l1 should collect its to-self payment.
+        bitcoind.generate_block(10)
         l1.daemon.wait_for_log('Broadcasting OUR_DELAYED_RETURN_TO_WALLET .* to resolve OUR_UNILATERAL/DELAYED_OUTPUT_TO_US')
         l1.daemon.wait_for_log('sendrawtx exit 0')