The only one India is messing with is the Chenab, and only because it messes up Pakistan's Rice and Sugar exports (major forex provider for Pakistan, and the supply chain is heavily owned by Pakistan's MilBus). Kharif sowing season ends in a couple weeks so messing with the Chenab for 3-4 weeks is enough to destroy the rice harvest in Northeast Punjab.
I recommend reading Ayesha Siddiqui's "Military Inc" to understand the Pakistani army (she was forced into exile because of the book), and "Army and Nation" by Steven Wilkinson to understand India's army.