Feel sorry for the cast who are supposed to zip their lips, and their cameras, I guess. They have some fun, post a pic, and immediately have to delete it, as it reveals some big secret. Too late, some sharp eyed person took a screen shot, and posts it, which breaks the news which soon is all over.
To be fair to Galen Gering (Rafe) though, that Instagram video from September 13 first spoiled Brandon Barash's (Stefan) return, as he was seen seated on a new set (a garage). But at least it was a far-enough away photo to not fully confirm his return at that point.