I’ve read another thread that this has been an issue since at least February 2023, even further back to the beginning of Overwatch 2.
Having reached out to support with screenshots of this error & proof; their only solution is to create a topic in the bug report forum… As they cannot seemingly make any adjustments.
It’s to be noted in their response that they are fully aware of this bug, with no ETA on a potential fix or if they even plan on fixing it to begin with.
In fact, incorrect and missing end-of-season competitive rewards has been a bug since Season 36 of Overwatch 1. You are not alone in experiencing this bug. Linking 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 (Seasons 1-3). Please help in spreading the word about this megathread and other related threads, we must demand the Developers to give us the rewards we rightfully earned.