devtrackers.gg
Normally wouldn't post info like this on a (well played) meme, but since this is the biggest thread on the topic: This should be happening way less frequently as of an hour or so ago.
We put a temporary rate-limit on progression due to heavy load during Lucky Lanterns, which is why earned XP was not showing up at the end of a match, but might appear in the main menu or elsewhere a few minutes later. No XP was lost during this rate-limit, it was only appearing late. Sorry for the trouble, all, and thanks for being patient and/or channeling your frustration into top-tier meme content.