Why does it not set the player's walkspeed to 16?

This script is fired when the player clicks the exit button on a shop. This script for some reason doesn't change the player's walkspeed

game.ReplicatedStorage.CloseShop.OnServerEvent:Connect(function(player)
	
	game.Workspace[player.Name].HumanoidRootPart.CFrame=game.Workspace.SHOP.ExitShopPart.CFrame


	game.Workspace:FindFirstChild(player.Name).Humanoid.WalkSpeed = 16
	
end)

And whats weird is that if I change this value to 17 or 15 it changes. Why is it doing this?

Okay, so if anybody gets this same problem I found the fix.

What i did to combat this problem was that I made a remote event which was fired when the player closed the shop.

Script

game.ReplicatedStorage.CloseShop.OnServerEvent:Connect(function(player)
	
game.Workspace[player.Name].HumanoidRootPart.CFrame=game.Workspace.SHOP.ExitShopPart.CFrame

	game.ReplicatedStorage.SetSpeed:FireClient(player) -- the remote event that was fired
	
end)

Then, I had a local script listening for the remote event. When the event was fired, this script set the player's walkspeed to 16

Local script

local replicatedStorage = game:GetService("ReplicatedStorage")

replicatedStorage.SetSpeed.OnClientEvent:Connect(function()
	game.Players.LocalPlayer.Character.Humanoid.WalkSpeed = 16
end)

I still have no idea why my script didn't like to change the walkspeed to 16 but this is the fix!