all coins are unpredictable , not just bitcoincash. the reason why bitcoincash pumped so much its because it has got some potential and advantage that other forked coins and altcoins doesnt have, infact it can also beat bitcoin in terms of usage because it does not a have a scalability issues which means it can work faster becuase of bigger blocks support therfore transactions can be mined and proccessed faster simulateously without having network congestions that bitcoin usually have due to spamming of transactions with smaller fees. overall i possibly believe that bitcoincash will have a comeback and boom again next time.