andrasz, in my previous experience with armchair investigation, in absence of any info from officials good beacons are internal urgent documents, released by authorities. In case of Red Wings disaster in VKO it was telegram about reverse engagement, in case of Kazan - telegram about go-around technique and so on.
As we doesn't see anything similar in this case - posted NOTAMs was not released AFTER accident and Kolavia A321 now allowed to fly - I think that real experts have not much more confidence in real reason then we, pprune detectives.