It still boils down to the adage to shoot what you prefer and feel most comfortable with. The break down sounds more like a form issue involving back tension, which may occur with either light or heavy bows. There may be a lot of factors involved I don't know about, but I don't consider 50# a heavy bow for a healthy adult of normal strength. A lighter bow will not eliminate those days where things sometimes don't work like you expect them to, but that is part of trad archery. (Remember, this is only my opinion so no need to rain down condemnation on me.) Since you commonly shoot this bow well, it does not seem you are over bowed, which is why I would suggest back tension as a likely culprit.