If the single-asset strategy you are deposited into involves folding, your balance will slowly decrease due to borrowing costs until a harvest occurs. When this takes place, Snowball is selling the rewards you've accumulated for your original underlying asset, and your balance will increase by a value much higher than what it decreased by previously. At the moment, these harvests take place 2-3 times a day and can be tracked through the #harvests channel on our Discord server.