Missing authority when trying to broadcast a vote on golos

[pharesim]

I copied a script that works on steem and changed the node, but the transactions are refused by wss://ws.golos.io The Missing Posting Authority error contains a "sigs" param in the vote which is always different.

Relevant code:

node = 'wss://ws.golos.io'
rpc = SteemNodeRPC(node)
wif = '5..'

def castvote(op):
  expiration = transactions.formatTimeFromNow(180)
  ref_block_num, ref_block_prefix = transactions.getBlockParams(rpc)
  tx     = transactions.Signed_Transaction(ref_block_num=ref_block_num,
                                         ref_block_prefix=ref_block_prefix,
                                         expiration=expiration,
                                         operations=[op])
  tx = tx.sign([wif])
  rpc.broadcast_transaction(tx.json(), api="network_broadcast")

nop = transactions.Vote(
          **{"voter": votewith,
             "author": author,
             "permlink": permlink,
             "weight": int(weight*100)}
      )
      castvote(transactions.Operation(nop))

2 example replies:

 {"ops":[["vote",{"voter":"pharesim","author":"romapush","permlink":"karl-v","weight":100}]],"sigs":["GLS6x2W3CcR4eeKwTg8a23XkdcfySivi4xVPk76FVpgbE3MzduV2z"]}

{"ops":[["vote",{"voter":"pharesim","author":"romapush","permlink":"karl-v","weight":100}]],"sigs":["GLS8by3pXWPTtdZdbu7pckbrhZaXVdxdXgkHtpxukKza2HEc6QDmT"]}
    th_a  transaction.cpp:164 verify_authority