Why are approved time cards sitting in submitted status?

We've had several reports of Approved time cards staying in a Submitted status. I've witnessed it myself when a supervisor approves the time card in the BPM worklist and the time card stays in a Submitted status. I've included screenshots of one example. This is happening in both Firefox and Chrome. And the browser caches have been cleared. This has only started happening in the last couple months, and they're employees who have been here for several years. This is becoming more frequent. So why are approved time cards sitting in submitted status even after being approved? And how do