It is more than possible that blockchain.info simply has the info wrong, though I'm sure there is a much better explanation for this.
No, I'm talking about the timestamp field which is part of the block, not the "received time" field which is just from blockchain.info's point of view. Blockexplorer.com also shows those two timestamps out of order:https://blockexplorer.com/block/00000000000008729cb2580c281200c2c2296757def0d8b27f4b7b8a047d4d34https://blockexplorer.com/block/00000000000000b480d06cbe1c462c76e8ca51587f4c37cf65651d5b47eccfae
In other news, two more IPs have been mining empty blocks in recent days, including two in a row a couple hours ago:http://blockchain.info/block-height/171806
(relayed by 22.214.171.124)http://blockchain.info/block-height/171807
(relayed by 126.96.36.199)
Here are blockchain.info's transactions relayed lists for all four of the IPs I've seen mining empty blocks recently:http://blockchain.info/ip-address/188.8.131.52
(29 empty blocks between March 3 and March 7)http://blockchain.info/ip-address/184.108.40.206
(62 empty blocks between March 12th and today)http://blockchain.info/ip-address/220.127.116.11
(9 empty blocks between March 14th and today)http://blockchain.info/ip-address/18.104.22.168
(6 empty blocks between March 16th and today)
If all four are the same entity, I think they have
(edit: maybe not) 15% of the hash power now (the amount estimated by https://www.privateinternetaccess.com/blog/2012/03/bitcoin-war-the-first-real-threat-to-bitcoin/
Also worth noting, these IPs are relaying new transactions too, aside from winning blocks.