There's [[ https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#Wikipedia_app_vandalism | a report at en.wp ]] by @Nthep, about "a rash of vandalism occurring adding porn pictures to articles that are featuring in 'In the news' e.g. [[https://en.wikipedia.org/wiki/North_India |North India]] and I can't work out how to remove the vandalism."
@TheDJ points out that the content would have come [[https://en.wikipedia.org/api/rest_v1/feed/featured/2017/08/31| via]] the [[https://en.wikipedia.org/api/rest_v1/#!/Feed/aggregatedFeed | "aggregated featured content"]] RESTBase feed (where that article and presumably also its vandalized image appeared that day), and suggests that aggressive caching may be at fault. We'd like to find out if there's a specific bug.
Thanks!