You are not alone in experiencing this bug. I’ve linked the competitive bugs megathread at the bottom of this post, which archives and documents almost every competitive bug. I put your thread under: Not Appearing On Leaderboards (Season 6). Please help in spreading the word about this megathread and other related threads regarding these issues.
In your case, it might be an issue with your account not having Blizzard Authentification since that’s one of the three requirements for Top 500 eligibility that you didn’t mention. Here’s a thread about your missing Top 500 leaderboard placement issue if you’d like to read more about other potential solutions: The Competitive Bugs Megathread - #318 by Azdyph-1127.