Validating node running for several hours in a network of 6 nodes. Showed this error multiple times. Node does not fail. It's unclear if what was intended to stream did and if anything afterwards streamed successfully.
Update: Can confirm what was intended to stream did not, thus making this validator useless to the network since it could neither send messages about newly proposed blocks or messages about validation of blocks received.
If a node becomes unable to send messages, it should fail.