You don't "learn learnings" I agree but in my mind you _get_ learnings from the process of learning stuff. The same way you get findings from the process of finding stuff out. I'm a Swedish speaker and we have a dedicated word "lärdom" that we use like "learning" so that usage is very natural to me. "lessons learnt" is clunky to me and there we have another saying, "lära sig en läxa" that has the school connotations.