When one looks at the "Stats" page associated to a review task, one can see the number of additional review tasks required in order to earn a badge for that review task. The silver and gold badges continue to show progress "toward" the badge even after the badge is awarded. For example, after just another negative 9,130 review tasks, I'll get a silver badge for the Close queue!
This has been fixed. Details are available in my answer on MSE: https://meta.stackexchange.com/a/348957/235711