Missed ‘mandatory appointment’ while TDY. That’s not how that works right?

Currently on a training TDY. Got a text from my boss that I didn’t report to CSS for a piss test. Of course he knows I’m not there and he’s got me. But excuse me if I’m wrong but that shouldn’t happen right?

Once you’re TDY/PTDY you’re off the tracker right? Is this CSS mistake?