What causes the water to flutter out of one faucet in house only on hot side?

Water Hammer: Water hammer is when excessive pressure from sudden changes in water flow cause pipes to jerk or vibrate, leading to banging or hammering sounds. This pressure increase can occur when a faucet is quickly shut off or when a large appliance (like a washing machine or dishwasher) shuts off its water supply. If your house has a single-handle faucet on the hot water side only and this water hammer is the culprit, installing a pressure-balance valve can help reduce or eliminate the fluttering.

High Water Pressure: Water pressure that's too high for your home's plumbing system can cause pipes and fixtures to shake and can lead to leaks. If your home has a single-handle faucet with this issue, installing a pressure-reducing valve can solve it.

Defective Parts: Sometimes, worn-out or defective faucet parts, like washers or O-rings, can also cause water to sputter or flutter. When this happens, replacing the affected parts should resolve the issue.