Just noticed recently, suddenly all of the series posters of my Anime series "disappeared". It actually didn't disappear, but it changed, and was only saved as poster, not folder. I'm assuming since I just recently installed the Anime plugin, that it is was updated new info for my Anime, but it's odd that it replaced/removed the posters, but also that only posters was saved. I'm not sure if this is an issue with xbmc metadata saver as well, but I'd say something is amiss.
Thanks
edit: It actually decided Eureka (syfy show) was Eureka Seven and changed a bunch of metadata. I would definitely default to not changing, only adding on.