We can still get a warning:
lightningd-1 2025-12-10T01:11:07.232Z DEBUG 022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59-connectd: Received WIRE_WARNING: WARNING: channel_announcement: no unspent txout 109x1x1
This has nothing to do with l1 talking about the original channel
(which would be 103x1x): it's because l2's gossipd (being the node
which does the splice) immediately forgets the pre-splice id. If l1
sends some gossip, it will get a warning message.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>