IsA function doesnt work on object value in XP script?

im trying to give the player XP when they kill an enemy, ive tagged the enemy the player hits with an Object tag with the value being the players name and giving them xp from a script in the enemy they are attacking, the problem is that the script only gets up to "print("NPC Died")

local NPC = script.Parent
local Humanoid = NPC:WaitForChild("Humanoid")

local Players = game:GetService("Players")

local respawnTime = 5

local plrAttacked = {}

local npc_Clone = NPC:Clone()
Humanoid:GetPropertyChangedSignal("Health"):Connect(function()
    if Humanoid.Health <= 0 then
        print("NPC Died")
        for _, plrs in pairs(Humanoid:GetChildren()) do
            if plrs:IsA("ObjectValue") then
                print("is object")
                local plrFound = Players:FindFirstChild(plrs).Value
                print("Got Value")
                if plrFound then
                    local PlrStats = plrFound:FindFirstChild("Attributes")
                    local PlrCurrency = plrFound:FindFirstChild("Leaderstats")
                    if PlrStats then
                        local Exp = PlrStats:FindFirstChild("EXP")
                        local Shards = PlrCurrency:FindFirstChild("Shards")
                        local Gold = PlrCurrency:FindFirstChild("Gold")
                        if Exp and Shards and Gold then
                            Exp.Value += 25
                            Shards.Value += 1
                            Gold.Value += 20
                        end
                    end
                end
            end
        end

        wait(respawnTime)
        npc_Clone.Parent = workspace
        NPC:Destroy()
    end
end)