Why cant the script detect "Engine" when it is there?

So in a script that I've had for a few years, its worked fine until a recent update that made some things break. For instence this bit I cut out from the script. Engine isn't being detected but I know its present, and the CheckExists function does work because its being used throughout the script.

What could be causing the issue?

local BFM = {}

function BFM:CheckExists(object,parent,giveError,returnIfFalse) --Check if Object exists
    if parent:FindFirstChild(object) ~= nil then return parent[object]
    else
        if giveError == true then self:msg("Cannot find specified object, "..object..", in parent, "..parent.Name..".","Error",true,true,false,false,false,false) end
        return returnIfFalse
    end
end


local function adminCMD(player,cmd)
    if BFM:CheckExists("Engine",player.PlayerGui,true,false) ~= false then  --Engine isnt being detected.
    else error = error + 1 end
end