I'd rather have bugs come in through any possible channel than try to enforce "github only", so thanks for putting it in.
There should have been no change, so this is some sort of regression. The Talents tab might allow you to earn TP still without the Become Legend button appearing, Retire button never gave TP, but that would be at best a workaround the issue if it still works.
This is going into the bug tracker and will be a high priority.