I'm hearing "exploded".
I'm only saying it could be bavar because officials have stated bavar will be tested on a BM. Otherwise I'd say it would indeed be a test failure, probably in the reentry stage if it exploded or broke apart.
At the moment I think it was a bavar test, though I'm not going to rule out a test failure out of sheer nationalism.
I doubt that.
First of all, indications are it "exploded", not split.
Second of all, MIRV release does not happen during reentry. It happens just before or as the warhead/missile leaves the atmosphere. Assuming the usual 2000 km range, at 1000 km the missile would just be about to leave the atmosphere... it would have long ago exited it, possibly even on its way back down considering missile tests are rarely done at full range.
The reentry phase is the most likely time of explosion (given the immense temperatures of reentry) but also when the Bavar-373 is most likely to be tested since I highly doubt it intercepts exoatmospherically.