Once Hailed as Unhackable, Blockchains Are Now Getting Hacked

TL;DR consensus models are flawed in that an actor with enough computing power can manipulate the system. A blockchain of hashes is not in it self flawed, but it can be rewritten if someone overpowers the rest of the system.

This has always been the primary fear of all Blockchains, given enough time we are starting to see it occur in specific places.