Had some weird problems with miners messing around with block timing to mine at high rate with lower difficulty.
http://findblocks.com/explorer/FELX?height=23982021-06-07 14:47:53
http://findblocks.com/explorer/FELX?height=23992021-06-07 14:42:54
These two miners mined block with 5 minute difference, producing blocks every second with low difficulty from the blockchain.
Digishield update difficulty after each block, but I think blocks with earlier time was messing with it's 60 seconds window of hash rate calculation.
The blockchain code was based on Dogecoin code.