2007 Audi S4 clutch issue

Hello to anyone who may be reading this.

I’m having a clutch issue with my 2007 Audi S4. It has 100k miles, and I’m not sure whether the clutch is original or not. I’ve owned the car since it had 82k miles and have never noticed any slipping or signs of wear, even on days when I’m driving hard.

During an autocross day, I suddenly couldn’t shift the car. The clutch pedal still had pressure, but it felt softer and just “off.” I found that I could turn the car off, put it into first or reverse, turn it back on, and then slowly release the clutch to get it moving. I could also rev-match my shifts, so I drove it home that way. After about 10 minutes of driving, I stopped at a light and noticed I was able to shift normally again, although the pedal still didn’t feel quite right. I made it home, but the next day, after sitting overnight, the issue came back.

I’ve driven it around my neighborhood a few times to see if it would “fix” itself again, but it hasn’t. I’ve also checked for leaks(none)and fully bled the system with no improvement.

What would be the likely culprit, or where should I start?