Comment by thesausageking

If the network goes down completely, as it's coming back up, groups of nodes will start adding blocks before all of the other nodes are back online. When connectivity is completely restored, you end up with different parallel chains, each of which thinks it's the main chain. With Bitcoin, there's a simple, deterministic way to decide which chain to trust: the one which has had the most work done it. With Algorand, it's not clear what would happen.