Change to TreeProto:run

function TreeProto:run(dt)
    if self.running then
        -- warn(debug.traceback("Tried to run BehaviorTree while it was already running"))
        return
    end

    local nodes = self.nodes
    local obj = self.object
    local i = self.index
    local nodeCount = #nodes

    local didResume = self.paused
    self.paused = false
    self.running = true

    local nodeResult -- MY EDIT *******************************************************************************

    while i <= nodeCount do
        local node = nodes[i]

        if node.type == "task" then
            local task = node.task

            if didResume then
                didResume = false
            elseif node.start then
                node.start(task, obj, dt)
            end

            node.status = nil
            node.run(task, obj, dt)

            if not node.status then
                warn("node.run did not call success, running or fail, acting as fail")
                node.status = "fail"
            end

            if node.status == "running" then
                self.paused = true
                break
            elseif node.status == "success" then
                if node.finish then
                    node.finish(task, obj, dt)
                end
                i = node.onsuccess

                nodeResult = "success" -- MY EDIT *******************************************************************************
            elseif node.status == "fail" then
                if node.finish then
                    node.finish(task, obj, dt)
                end
                i = node.onfail

                nodeResult = "fail" -- MY EDIT *******************************************************************************
            else
                error("bad node.status")
            end
        elseif node.type == "random" then
            i = node.indices[math.random(1, #node.indices)]
        else
            error("bad node.type")
        end
    end

    self.index = i <= nodeCount and i or 1
    self.running = false

    -- MY EDIT *******************************************************************************
    if i == nodeCount+1 then
        return nodeResult
    else
        return "running"
    end
end