In 2016, it seemed like Volkswagen had neatly managed to put the diesel emissions scandal behind it.

Sure, there still were some ongoing state-level actions, but all the big stuff was supposedly over, wrapped up in a $14.7 billion deal that covered a class action by VW owners plus claims by the Department of Justice, the EPA, the Federal Trade Commission, the California Air Resources Board and attorneys general of 44 states, the District of Columbia and Puerto Rico.