I was recently reviewing this diff: https://en.wikisource.org/w/index.php?title=Index:Nationalism.djvu&diff=next&oldid=9918635
I noticed that some of the fields, e.g. Title and Author, were not in English, but what appeared to be an Indian language (I'm not exactly sure which). I then purged the page, and it went back to English.
The editor who made the edit says on his user page he is Punjabi: https://en.wikisource.org/wiki/User:Satdeep_Gill
Is it possible I was seeing a cached version of the page that was generated for him, with a different interface language? That would be bad, but also I'm not sure how that would work as some of the text was still in English.