The other day I removed the chain to clean up.
After it was nice and clean, I hurried to install it and lube - was lunch time or something.
A quick ride to see if all looks good - everything looked fine but seems making some noise.
Next day, I do a quick lube, clean it and go to a short ride.
After some 4 miles and the strange noise, I look the rear derailleur and what the f*&%#$@????
The chain was outside (in front) of the metal that is in the middle of the cage plates - between the jockey and idler.
Turned around and get home slowly and fixed it.
It that metal to protect the chain/drivetrain in case of some hazard?
Since didn't have anything to detach the quick link, turned around and went back home...