As I said, as soon as I made reqPnLSingle request, all subsequent orders-related errors started to come with that reqId instead of orderId. There were no errors related to reqPnLSingle itself. I would not probably believe it if I had not seen it with my own eyes. As soon as I blocked the reqPnLSingle, everything was back to normal.
I can't rule out the possibility that something in my code was causing it, but it's still weird, considering the support confirmed it's normally expected behaviour.
I will try to recreate the conditions once I get a chance.
