diff --git a/contrib/pyln-testing/pyln/testing/utils.py b/contrib/pyln-testing/pyln/testing/utils.py
index 29db7af2e..cc3e3d362 100644
--- a/contrib/pyln-testing/pyln/testing/utils.py
+++ b/contrib/pyln-testing/pyln/testing/utils.py
@@ -864,8 +864,7 @@ class LightningNode(object):
                 txnum = i
 
         scid = "{}x{}x{}".format(self.bitcoin.rpc.getblockcount(),
-                                 txnum,
-                                 get_tx_p2wsh_outnum(self.bitcoin, res['tx'], amount))
+                                 txnum, res['outnum'])
 
         if wait_for_active:
             self.wait_channel_active(scid)