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But why new blocks was not shown to official chain right from the start!?
Perhaps there is malicious miner which has more than 50% of network hashrate.
He shows his 'private' chain to public chain/wallets with delay just when his chain better (in terms of found blocks) than public chain.
Almost in all cases when reorganization has happened, 'alternate' chain has more blocks than public chain.
Regarding those 13 disconnects:
Here the chain splits. Following both branches ( links after "Next Block" ), I believe one branch mostly awards familiar coinmine.pl address (YESJtirJQJsDRTVS67UuuPZfeoJ6YWojwt), while the other (it's coinbase rewards 15Lxek3tUvxzDhjX1dtC3Znz6xXi62HtvF) is competing branch that refuses to mine on top of block of first one, but it does not seem to withold blocks until later.
Two steps later It can be seen that it also bumps up difficulty (perhaps because of different times), so it is able to overwrite best branch inspite of that one having POS blocks included.
I have been monitoring/investigating this situation for the past few days. And I am noticing that the network hash/s spikes around 12am-3pm PST (7am-10am GMT) to over 200 khash/s and then it reduces to as low as 100 khash/s at around 12pm-3pm PST (7pm-10pm GMT.
Looking at the statistics on yac.coinmine.pl, I have seen the block reward time get as low as 32 seconds when the network hashrate is at its highest. Also, looking at
http://explore.grokonet.com/?inflation=1, you can see inflation spike to 100% and then back to 50% cyclically with a period of about 24 hours over the last few weeks.
Could it be some student at a university in eastern Europe who has access to a few supercomputers at only certain times of the day, every day? Could it be some selfish/malicious miner (botnet operator perhaps) who is systematically playing off of the difficulty adjustments to optimize the benefits of selfish mining? By the way, it seems that the time per block has the 'biggest' impact vs someone having over a third (or more) of the network hashrate.
There is 'kicker here... I believe whoever is doing it is NOT mining and dumping. In fact, that person(s) could very well be mining and pumping? When I attempted to even out the network by pointing some resources to coinmine.pl, evening out the network, it seemed that automatic sale orders started up on cryptsy. When I pointed my resources away from coinmine, the sell orders stopped.
It is an interesting situation. Since I don't know who this 'selfish' miner is nor his intentions, I would rather help out coinmine.pl (I think there is a chinese pool as well somewhere with about 60-80 khash/s of hashing power?) and allow smaller miners to mine and dump a few thousand yac a day vs allowing one entity to have a near monopoly on nearly 100,000 YAC created per day. However, the NFactor changes in less than 6 days, which will change the entire landscape in terms of blockchain transaction processing...