Deleting the Worker in the Hub Overview helped, but now the error comes slowly back on the first worker again

ETH: 11/29/17-03:17:50 - SHARE FOUND - (GPU 3)
ETH: Received error: {"id":4,"result":null,"error":[21,"jobnotfound"]}

don't know if the hub send job twice, maby internal problems with ids ?

Eidt:  ETC via ethash 17020 port