It is on my 05 CTT with Bose system (fiber optic connector to radio).

So I was driving the other day and just happen to break on the hard side, and noticed that the radio unit reset itself (screen went black, then Porsche logo came on, then back to radio).
It did that a couple times. Got home, removed the radio (which was hot). Unplugged the wires in rear of the unit. Left as is (had something to do).
Later, plug it all together, and all seems fine. For about a week.

Today, driving to a friend, same thing, radio reboots itself. See the Porsche white background with logo, then sometimes to to radio, and sometimes goes blank again.
Since then, nothing seems to work. When unplugged, noticed unit was very hot again (the heat sink in rear and the chassis too).
When made the car quiet, noticed that there was an amp or something else from the rear of the car, I could hear a fan spun up trying to cool whatever it was that was running. When I unplugged the connector paired with the fiber optic connector the fan on whatever piece of hardware stops running after about 5 seconds. Towards the end of troubleshooting, noticed that when the connector is plugged in, the fan is not running when I become quiet (but that could be due to the unit not being hot yet).
Resets itself many times if left alone. When I press the 1+4+8 buttons to reset, it will, but sometimes will go blank until I reset again. sometimes press the power button to turn it on, it will, but when radio comes on, I can only work the controls for about 2 seconds (enough to change station or volume a bit). After I do the one thing I can, the buttons will not work. Have to reset the unit again. Then back to square 1. Either buttons do not work, or will for just a short time again just like earlier.

So now, ended up disconnecting that connector (which cuts the power off to the unit). Hoping someone on here can give tips to do PD and hopefully resolve this issue. Thanks in advance.

 

UPDATE:

So I was playing with the head unit today.
Unplugged the connectors, trying to figure out if there is connection problem, etc.
Unplugged, checked and moved all the wires in the area. Nothing. Same story - the unit periodically reboots itself or just appears to freeze (at which point I have to push 1+4+ to reset the unit).
When unit resets, I sometimes am momentarily able to change station or volume (or whatever button I press). After about half a second, unable to change stations, volume, anything that can be done with a button at front of the unit, I lose that capability in about half a second after unit comes up from reset.

Finally, decided to isolate the connectors, so started with the top wide connection at rear (as looking at the rear of unit, highest plugged in connection).
Keeping all connectors in the unit, unplugged that top connector. Nothing, still able to hear everything, still unable to change stations or volume or make any changes with buttons at front.
Plugged it back in.
Unplugging the connector under the top one causes unit to lose power all together (from experience in this PD), so decided to keep it in.

Just for chits and giggles, deceded to unplug the power connector and unplug the fiber connection. Then plugged the power connection back in while the fiber cable was out.
No sound as expected, but noticed that now I am able to change stations, volume, pretty much everything this unit is supposed to do, but sound missing.
So I decide to bring connector close to the plug in site. Enough for the links to line up with transceivers. Notice that I now have audio in addition to ability to use front buttons.

COOL.

Decided to push the connection back in further but not all the way. All works great!!!!
At this point, getting really excited, and decide to push the connection in almost all the way (to the point of almost clicking in). ALL WORKS STILL!!

Decide to very gently push the connector to click in. ALL OK!
Powered off/on/off/etc several times. All OK.
Started car, verified the system can turn off/on with key insert, and went for a short drive to make sure nav works fine. All OK!

As of now, everything is working fine. I put the screws to the unit and reattached the bezel to finish up the PD. Still working fine.

So it may be premature to try to replace unit with a new one...I hope. We will monitor to see how it turns out. Posting this up to give updates to anyone who encounters unit rebooting or appearing to freeze and not being able to use buttons on front.
Will check back in again in a few days.