Not really. The river was also closed to iran during the american ocupation. In fact the taliban actually released watter at some point. Less than they should have but more than the previous regime.

The border clashes have nothing to do with that and more to do with the taliban organization being run more like a mcdonalds than a regular state. Sometimes a franchise owner decide they want to invade iran and get into a shootout. But the central command in unaware of that.