Sometimes on sending tradeoffer bot will receive error from steam: "There was an error sending your trade offer. Please try again later. (16)" but in 5-60 seconds unknownOfferSent event fires 1-3 times with this exact trade (I triple checked that I create offer only once, with logs too), one of these offers will behave as usual and all others (if there are others) will have status InvalidItems. Usually it happens when steam lags
Is it even possible? Or should I look for errors in my code?