Apparently, the argument was about the noise coming from the VIP tent next to the court. People were having lunch and just chatting away, not giving a damn. MVA didn't seem too happy about this from the start.
The discussion really started, however, when MVA hit a double fault in the second set. He just wouldn't shut up, Jérémy went to the net and told him to get on with it. The ATP supervisor was called, but I don't think it changed much. Anyway, they continued, Jérémy got his first break and that was it.
At least that is what I could pick up from the commentary on the livestream. Hope that helps.