Shift lever won't go back past Neutral to "R" and "P" after a drive.
 

Having issues with the shift lock on my c230 Komp Coupe;
Symptoms - now and then shift lever can't move past Neutral to Reverse and Park. Which means, the key is locked in ignition. The car can be restarted and driven and eventually it will work again.

Observations (may or may not be related to the issue): With the key out, the shifter can move freely to all positions (no park lock seems to be working).
If I put a tool through the hole in the coin holder depress the manual override, shifter will lock past Neutral like the symptom described above. Releasing it will let the Shift lever move freely again. However, doing the same when locked out has no effect.

Any ideas as to what could be going on with the interlock mechanism? I searched the Web and most of the issues were to do with "Shifter stuck in Park".

Sounds like there is a linkage issue. I found that my linkage was very lose when in park. But I have never had this issue so there may be other with a more in depth answer for you.

I'm guessing something broken and loose inside the shift mechanism. It can go for weeks without any issues and suddenly it would lock up few times in a day. I know for sure, the Park lock is not working. I'm guessing there is another lock mechanism to stop you from changing to Reverse from Drive when moving forward.

Found the culprit yesterday; a penny had fallen inside. Now I have the P Lock back and all seems to be working according to how it was intended. As for the "Coin" all I can think was, one of the POs had the ashtray with coins and one slipped through on braking hard. I squeezed in a flexible lagging rod to cover the space so this won't happen again.