Is Zerodha playing dirty tricks with Kuvera?

Zerodha launched its mutual fund product (coin app) very recently and here is what also happened.
Mutual fund player, Kuvera (now competitor) has noticed a sharp drop in its play store rating from 4.3 to 3.8 in 3 days.
Checkout Kuvera CTO, Mayank’s tweets.

Coincidence? What’s your take?