could it have to do with the change that allowed original attacking bombs to trigger when any enemy was within their max AOE?
It may be that the bombs trigger when a viable target is within their max aoe, but then at resolution of the effect a fast moving player may be just outside?
Maybe if they activate when a target is say within 90% of their max aoe (or if max AOE for targeting purposes was slightly reduced for a flying bomb compared to a stationary one?), then the target might get hits that stick more often?