http://en.wikipedia.org/w/api.php?action=query&format=json&titles=Translatewiki%2Enet&prop=pageimages&piprop=thumbnail&pithumbsize=150&redirects=true used to return the logo (seen on https://en.wikipedia.org/wiki/Translatewiki.net) but now it returns unreadable text from the video thumbnail.
closed this task as a duplicate of T87336: PageImages shouldn't return images that are not in the lead section.
The video is actually a plausible image to represent the article, so I don't think the proposed solution is a correct one for the specific case. It may be fine to decline this report though.
Right now I'm purely trying to understand what this bug means.
The bug report is about the suggested image, https://upload.wikimedia.org/wikipedia/commons/thumb/3/37/Translating_the_wiki_way.webm/150px--Translating_the_wiki_way.webm.jpg , being very ugly (unreadable text over white). This could happen with any video placed in any point of the article, as the default thumbnail for a video is essentially random.
The article does not show that thumbnail, but a different one set via |thumbtime.