Weld causes character to stop moving only when sprinting

[DemonOfPoem]

You can write your topic however you want, but you need to answer these questions:

1. What do you want to achieve? Keep it simple and clear!
   I want to be able to weld a tool to the character while sprinting and it not stop the character. it does not stop me when im not running.

Here is the weld script in server:

Character.ChildAdded:Connect(function(Item)

	if Item:IsA("Tool") and Item:FindFirstChild("Weapon") then
		if HoldingOutWeapon then 
			return
		end
		
		HoldingOutWeapon = true
		local Weapon = ServerStorage.Weapons:FindFirstChild(Item.Name)
		
		if not Weapon then 
			return
		end 
		
		Weapon = Weapon:Clone()
		
		Weapon.Parent = Character
		Weapon.Weld.Part0 = Character.Hilt
		Weapon.Weld.Part1 = Weapon
		
		EquippedWeapon = Weapon
	end
end)

Here is sprint script in client:

local function doSprint()
	if not sprinting then
		if canSprint() then
			sprinting = true
			cdBeforeSprintAgain = true
			
			hum.WalkSpeed = 25
			--Add weapon sprint anims later
			
			normalsprint:Play()
		end
	elseif sprinting then
		sprinting = false
		
		hum.WalkSpeed = 16
		normalsprint:Stop()
		
		task.wait(.5)
		cdBeforeSprintAgain = false
	end
end

local function InputBegan(input, typing)
	if typing then return end
	
	--Run
	if input.KeyCode == Enum.KeyCode.LeftShift and not cdBeforeSprintAgain then
		if swimming then return end
		doSprint()
	end
	--

[DemonOfPoem]

EDIT: This is a studio bug that does not occur in real game