From the news article cited:

"The (Nature) article is saying that Wikipedia has a third more errors" than Britannica, said Jorge Cauz, president of Encyclopedia Britannica.

But Cauz and editor in chief Dale Hoiberg also said they were concerned that Nature had not specified the problems that it had found in Britannica.

"We've asked them a number of questions about the process they used," Hoiberg said. "They said in (their article) that the inaccuracies included errors, omissions and misleading statements. But there's no indication of how many of each. So we're very eager to look at that and explore it because we take it very seriously."

And that was six years ago. More information needed.