I have been coming across this error at times , mostly when i am publishing too many items too soon into the streams :
chain2: publish stream1 abc37467317911196.6 123456789a
{"method":"publish","params":["stream1","abc37467317911196.6","123456789a"],"id":1,"chain_name":"chain2"}
error code: -4
error message:
Error: The transaction was rejected: 64: Metadata script rejected - Inputs don't belong to valid publisher
chain2:
I quit and run it and the same command executes well. Please let me know if this is a bug.