Why does the KeyframeReached event not fire? [UNSOLVED]

I'm trying to make an animation not run a second time until it is finished running the first time. The problem is, however, that the animation only runs once because the KeyframeReached event does not fire. This is a local script in starter gui and nothing appears in the output -- at all.

local plr = game.Players.LocalPlayer
	repeat wait() until plr.Character
local hum = plr.Character:WaitForChild("Humanoid")
local mouse = plr:GetMouse()
local anim = workspace:WaitForChild("Animation")
local canPlay = true

mouse.KeyDown:connect(function(key)
	if key:lower() == "q" and canPlay then
		canPlay = false
		local animTrack = hum:LoadAnimation(anim)
		
		animTrack.KeyframeReached:connect(function(name)
			print("fired")--Does not print
			print(name)--Does not print
			if name == "End" then
				canPlay = true
			end
		end)
		
		animTrack:Play()
	end
end)

The only possibility I can think of is that the animation only has one keyframe, but I'm doubtful that the aforementioned instance is the case. Unless the issue has to do with a bug in animations, the issue is most likely how you ran the script. Also, the issue could also be with the script itself( other scripts tampering with the script ).