I was diamond 5 in open q and it gave me plat reward why
The 7 win 20 loss system doesn’t preventing your true rank from changing it just prevents you from being able to see it changing. But, if you believe this is a bug, I’m linking my post in case you would like to read more about this issue: Comprehensive Thread Of All Top 500/Competitive Bugs. I put your thread under: Incorrect/Missing Competitive Rewards For All Ranks (Seasons 1 & 2).