Help with camera bounce

The problem is whenever I move around in a small circular motion and then moving normally when the bounceTime is close to tau (2*pi), the camera becomes very bouncy for a brief moment before returning back to a normal frequency.

local tau = 2 * math.pi
local maxCameraSpeed = 100
local maxAmplitude = 0.3

local function Lerp(start, goal, t)
	return start + (goal - start) * t
end

local function OnCharacterAdded(character)
	local isMoving = false
	local bounceTime = 0
	local cameraSpeed = 0
	local amplitude = 0
	local currentCameraSpeed = 0
	local currentAmplitude = 0

	local humanoid = character:WaitForChild("Humanoid")

	humanoid.Running:Connect(function(speed)
		isMoving = speed > 0
		cameraSpeed = speed * 1.5
		amplitude = speed * 0.02
	end)

	connection = RunService.PreRender:Connect(function(delta)
		bounceTime = (bounceTime + delta) % tau

		currentCameraSpeed = math.min(Lerp(currentCameraSpeed, cameraSpeed, delta), maxCameraSpeed)
		currentAmplitude = math.min(Lerp(currentAmplitude, amplitude, delta), maxAmplitude)

		camera.CFrame += Vector3.new(0, math.sin(bounceTime * currentCameraSpeed) * currentAmplitude, 0)
	end)
end

I dont understand why are you using deltatime as alpha for lerp operation?