It's called "weak synchrony".

The Time Warp Attack, which was hypothetical, was implemented effectively against the Verge cryptocurrency, which succeeded in pausing the chain and allowing the attacker to issue as many blocks as they wanted to until the node runners shut them down.

The vulnerability that enabled this was an attempt to tighten the synchrony of the network, by, specifically, nodes adjusting their time offset to a tight margin of the average of the swarm.

All that was required was for one node to continuously poke at the network's measure of time until all nodes agreed there was no progress of time, and the attack basically then shut down the network.

The lesson of this story is that you can't make a consensus out of the time, without breaking the difficulty adjustment.