We encounter a new but critical issue since about 3 days ago when Jenkins master had an unexpected reboot.
Slaves (ssh) return this error and the only way to make them work again is to disconnect them and to reconnect them. After this they will work for some time but we have information that the problem appears again after some time.
We observed this behavior on 5-6 slaves and most of them had this version of Java
Master is running on newer java