I keep coming across people using “learnings” as a word in documents. Here is an example (scroll down to the bottom and you’ll spot it). Just a note for the incompetent: “learnings” is not a word. Go look it up in the dictionary…I dare you. See what comes up? “Learning”.
If you want to sound like Borat then keep using “learnings”. If you want to sound competent try “lessons learned”.