It's because of fluctuations of crypto prices. There's no such things as stable for all coins and tokens since crypto space makes bear market and bullish market. Even big investors make the risk of hold when they invest on a coin and not yet gets the earning profit until such time it's bullish and then profit comes. And good advise that if ever a coin price goes up, it's having a tendency to go bearish in the long run and that's the activity of all unstable crypto coins in the market.