When we send a %cork $plea we mark the flow as "closing" dropping any incoming message, except resends of the original %cork. But, the %bak $side could still sends us %boons and in that case we were ;; anything as a %plea, and crashing for every resend of the %boon, until the cork handshake gets handled on both sides, and messages stop being transmitted.

(seeing in the wild on ~norsyr-torryn)