Since they first existed:
67.76844935 BDR for 60 blocks - so not excellent, but not impossible: CDF[Erl] 0.842606
Since the halving (excluding the data before the halving):
63.99816529 BDR for 57 blocks CDF[Erl] 0.825166 (thus a little better)
But since the halving there are worse - the longer term figures are (usually) statistically more relevant
(there seems to be a v2 bmminer that's found no blocks so far, but the BDR is only 0.07520162)
They do have the worst luck and the worst CDF on the pool for miner types connected directly to the pool.
But the numbers aren't in the realms of improbability - and it doesn't include any using proxies.
However there is (only) one "proxy type" with a worse CDF
stratehm-stratum-proxy-0.8.0 7.76724928 BDR 3 blocks: CDF[Erl] 0.983517