Could just be a bunch of blocks found in quick succession, see if it holds. Unless someone built a lot of very fast chips it wouldn't make much sense to build a block of miners like that.
143 blocks in the last 1162 minutes averaging 8 minutes 8 seconds per block
That would be some pretty good luck.
edit: I went back a little further
351 blocks in the last 2753 minutes averaging 7 minutes 50.6 seconds per block
edit2: I took the last 10 blocks
99 minutes 17 seconds - 595.7 seconds per block... pretty much bang on!