July 2015 forks and SPV mining: Why did F2Pool and AntPool mine an unverfied chain for so long?
It seems that F2Pool implemented their version of SPV mining with insufficient thought to the effects it would have. The proof is right there in the blockchain: they they didn't implement a timeout. 

It was a financially expensive mistake, but miners are highly incentivized to decrease latency, so not implementing SPV mining would also have cost them money.