listener.log: "Subscription node down event still pending"

My listener locked up early this week,=20 so I decided to poke into the listener.log to see if there was anything suspicious
(didn't find anything.) But I do see a
lot of "WARNING: Subscription for node
down event still pending." No TNS-nnnnn
nor ORA-nnnnn error number associated
with it.

What is that warning about, and how do
I make it not be pending?

TIA

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