Earlier this week, European negotiators sat in a conference room in Brussels and debated for nearly 24 straight hours — dozing off at times and working a self-service coffee machine so hard that it broke.

They came with a singular mission: reaching an agreement to regulate artificial intelligence. And they didn’t quite get there. But the EU’s internal market chief, Thierry Breton, didn’t want a long break over the weekend that would give lobbyists more time to weigh in, according to people familiar with the matter.