Your balance is ultimately measured in Satoshis, not in your local currency. Because Sats are inherently tied to the price of Bitcoin, you may notice the balance on your Profile page fluctuating. For example, if Bitcoin goes down 5% in a day, then your Sats will also be 5% less.
In other words, your rewards balance (as measured in your local currency) is changing with the price of Bitcoin!
* If the total number of Sats are reducing (not the local currency equivalent), then please check out this article: https://help.emberfund.io/hc/en-us/articles/24025897461531-My-mining-balance-was-reduced