You are not alone in experiencing this bug. Here’s a link to my post in case you’d like to read more about this issue: Comprehensive Thread Of All Top 500/Competitive Bugs. I’ve compiled a list of posts regarding similar bugs under: Incorrect End Of Season Competitive Rank And Rewards For Non-Top 500 Players (Seasons 1 & 2). Any help in spreading the word about this megathread would be greatly appreciated.