Intermittent TCP reset from pool member when large header + SSL

Opened support case, and they didn't help. We've spent many hours over phone and email with them. While they refrain from coming up with solutions, as they don't want to agree on existence of a problem we kept running our own investigation. As of today, after many tests we've done, I can tell that disabling Oneconnect solves the problem completely. I have not enough understanding why Oneconnect would cause this pattern in TCP segmentation but I know it goes away when there's no Oneconnect.