I have been mining with several rigs pointed to one pool (top 10 miner) for a while now and just stumbled across this by pure chance when looking at the mining logs of my rigs.
So I noticed, that the job/work the different mining rigs were receiving just milliseconds apart from each other was not the same across all rigs. One of my 5 rigs always received a different pow-headerhash to work on while the other 4 got matching headerhash (seedhash and target was the same across all rigs). All rigs are pointed to exactly the same pool-address and port (same server location), only the "worker" login is different (Rig1, Rig2, Rig3,...). I'm using same mining software and I made sure that it is not the devfee causing this while connecting to a different pool.
So obviously this pool must be running more than one node.
- One reason could be that the pool is choosing to mine a block with different transactions in it with some of the hashpower (but why?).
- Another more concerning reason could be, that one of the nodes has a different coinbase key set and would therefore be mining into a different wallet than the "main" pool-wallet. According to etherscan.io labeling there is only one known wallet belonging to this pool and it seems all the pools payouts come from this address. Since this is a serious allegation I don't want to name the pool here.
Or is there another simple explanation that I'm missing here?