This is the name of the city today, but this has not always been the case. In the past, Leuven was a bilingual city, and to many of the people who lived there, the city was known as Louvain.
Back then, a large proportion of Flemish intellectuals (including my grandparents) were French-speaking, which is a reason why there were so many French students and professors in Leuven/Louvain. Therefore I think that, in the context of the article, the "wrongness" of calling the city Louvain is not as clear-cut as you suggest.
To anyone interested in reading more reports (and more nuanced ones, in my opinion) from experienced meditators, I highly recommend the streamentry subreddit (https://old.reddit.com/r/streamentry).