I can't remember the exact timeline of events, but early on it was reported and assumed to be IDF, while others claimed it wasn't. Reports got walked back until there were more details, and now it's generally agreed that it was probably a Hamas rocket that exploded or something.
So I think the press may just be a little more careful with how they portray things when there is only one source or they are reporting on what other news organizations are saying. You know - like they should be doing anyway.