Why does mining revenue fluctuate

The  mining output fluctuates because of the changing hashrate and mining difficulty adjustment.

1) Hashrate Fluctuation:

When miners mine, the hashrate output is a fluctuating process. Affected by Service Charges, network, and miner status, the hashrate will fluctuate greatly, and it is the reason why your profit changes.

2) Mining difficulty adjustment:

2. Difficulty Adjustment: The network-wide difficulty of the encrypted digital currencies will be adjusted from time to time. Most of the time, the difficulty will increase, so the decrease of mining output is common when the hashrate of the miners does not change.