One of the nodes that I feed I have been getting the alert for a node down, which seems to be stemming from Calls reporting that it received the call already. In my mind, this would not classify as node down. I am wondering if it may be worth rethinking last seen and node down. I would think skipping the call would not classify, but obviously if nothing has been seen in X hours its node down. Additionally, I think I would classify a skew issue as node down as well as it could indicate an issue with the system's time.