https://warosu.org/jp/thread/S32275956#p32603091
If you see images of a 3D Ran MMD model being posted with little relevance, it is most likely one dedicated anon. They have previously been doing it in Ran-dedicated threads for some time, much to the frustration of at least one other anon. Wasn't sure if action was required there.
However, they've been branching out to other threads like the above, which is more clearly just spamming the same series of images. If you see something similarly irrelevant in another thread, I would WR/BR (at your discretion) and prune it all. It's not subtle.
As far as actual Ran (or fox, Yakumo family, fox, etc.) threads go, I think it is more a degree of clear intent to troll, and both the bait and the posts that take it should be considered at your discretion.