I’d be much more willing to believe the September date. It took them like a year to get Diablo 2 resurrected for ladder. Was supposed to come a few weeks after launch. I can almost guarantee you that they will be saying that they want to fix all of the problems that “appear” before launching the first ladder and will also delay for a long time here. Same drill as D2R.
But June will be the actual beta test. It’s just how the gaming world operates now, sadly.