Is this coin under attack ?

normally theres a few blocks every minute.

last hour has seen hundreds and I mean hundreds.

the diff was 120k +   and went down as low as 22k  even while the blocks were rolling in.

how can some farm  make loads of coins while making the diff fall.

sorry for my ignorance of how the diff works but I allways thought diff rises more coins found
to slow them to a pre calculated  average