Spinning/threadline reel maybe? If so.....read this please....
http://www.stripersonline.com/Pages/...m_braids.shtml
That may not necessarily be your problem, but it's some info. If it happens a lot, then there's cause for concern. If not, then perhaps the knot got in there while you spooled up at home.
Your rod casting weight is kind of a rough measure of what kind of lure weight that you can use efficiently with your rod. Too light or too heavy can give problems....like, too light and the rod can't load-up enough to cast the lure very far. And too heavy could overload the rod, and not only can't cast very far, but also could damage the rod.
Kenny