It was an airburst bomb.
The discrepancy between the epicenter crater and the rest of the damage cannot be explained by a faulty rocket.
The angle matches the angle in which a plane-dropped guided bomb would fall.
The crater was made by the metal head of the bomb.
The crater is tilted and matches the angle of an air-burst explosion in the air that would have such a tilted profile.
The and air-detonated bomb can be made to have its damage limited to where it's facing which seems to be the case here. A faulty rocket exploding all its fuel would not be this picky about the damage area.
Hamas mostly uses homemade rockets which would not cause this much damage to overwhelm Israel with costs; and if it was a 300kg syrian rocket the odds of malfunction would be lower, and the damage would be greater.
It could only have been by an air-burst explosion from a plane-dropped bomb.
