PoW processes stopped four times when receiving a new block

Created by: M5oul

When receiving a new block, Proof-of-work seems to be stopped four times:

2017-04-13T13:15:57+02:00 - info: Matched 3 zeros 000D2981C35C4D40364BDA668459980B09E26FE1E1B16F0014D3A5EFECAEA765 with Nonce = 20200000063340 for block#9976 by GfKERH
2017-04-13T13:15:59+02:00 - info: Matched 3 zeros 0006A207B47A7F3B6005F651AB28480179C19417B5A6F00F7251E05E0B24BF4D with Nonce = 20300000063629 for block#9976 by GfKERH
2017-04-13T13:16:04+02:00 - info: Matched 3 zeros 00041CB5FFF2F5BB520B617CC8506CB2A2A292AED734FC000C819B4E1BC592FB with Nonce = 20300000064152 for block#9976 by GfKERH
2017-04-13T13:16:16+02:00 - info: Block #9976 added to the blockchain in 442 ms
2017-04-13T13:16:16+02:00 - info: Stop proof-of-work worker #1
2017-04-13T13:16:16+02:00 - info: Stop proof-of-work worker #2
2017-04-13T13:16:16+02:00 - info: Stop proof-of-work worker #3
2017-04-13T13:16:16+02:00 - info: Stop proof-of-work worker #4
2017-04-13T13:16:16+02:00 - info: POST Block block#9976
2017-04-13T13:16:17+02:00 - warn: connect EHOSTUNREACH 192.168.0.12:8999
2017-04-13T13:16:17+02:00 - info: Peer 2yN8BRSkARcqE8NCxKMBiHfTpx1EvwULFn56Myf6qRmy unreachable: now considered as DOWN.
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #1
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #2
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #3
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #4
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #1
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #2
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #3
2017-04-13T13:16:17+02:00 - info: Stop proof-of-work worker #4
2017-04-13T13:16:17+02:00 - info: GIVEN proof-of-work for block#9976 with 5 leading zeros followed by [0-9A]! stop PoW for GfKERH
2017-04-13T13:16:17+02:00 - warn: The proof-of-work generation was canceled: Proof-of-work computation canceled because block received
2017-04-13T13:16:20+02:00 - info: Generating proof-of-work with 5 leading zeros followed by [0-9A]... (CPU usage set to 35%) for block#9977 GfKERH
2017-04-13T13:16:20+02:00 - info: Stop proof-of-work worker #1
2017-04-13T13:16:20+02:00 - info: Stop proof-of-work worker #2
2017-04-13T13:16:20+02:00 - info: Stop proof-of-work worker #3
2017-04-13T13:16:20+02:00 - info: Stop proof-of-work worker #4
2017-04-13T13:16:21+02:00 - info: Matched 3 zeros 000A7DAD4E62819708765268CD1AE4F612A04A6D752ED709BDE001D8DE7AD6AE with Nonce = 20300000000263 for block#9977 by GfKERH