Yes it is a known problem, pure engineering design.
I have a 2001 E320 T, both the front window and the rear window regulator
died.
The plastic slide part snapped both cases, unfortunately the replacement
window regulator
has the same week plastic part, so it will break again and again,
I guess Mercedes does not care about Quality anymore, other wise they would
redesign the part.
During the 5 years the rear window was used not more than 50 times,
the right front window maybe 100 times both of them break at the same place.

I had the symptoms with my 1997 E320. Perhaps you have the same problem.
I had to replace the window operator. This is a mechanical device
utilizing two pulleys and a wire. It attaches to the bottom of the
window.  It is driven by an electric motor. Fortunately the motor did
not need to be replaced, the wire/pulley assembly had failed. The
replacement parts cost about $150.00, and took me about four hours to
replace. To get at the window lift mechanism you need to remove the
upholstery on the inside of the door. To do the work you need your
normal small tools plus a pop rivet tool, and an electric drill to
remove the old rivets.

HTH,
EJ in NJ