how come the Mining Difficulty at https://block.bitvote.one/status
says    11865.02502900713
while Block Difficulty for block #528729 (just now) at Feb 5, 2018 10:16:32 PM was 0.18104591  
https://block.bitvote.one/block/000000030b302552d47a81bb659ead2fe57aca1c7ea3c1493ec14dde2592a568

Ive been seeing these high difficulty values on mining sites too  

for instance https://btv.coin-miners.info/index.php?page=statistics&action=pool
Current Difficulty   11,865.02502901
Est. Next Difficulty   0.19700022 (Change in 1479 Blocks)