hi there i saw the thread late, you're right its from the glove box i had the same problem, was in a rush and slammed the glove box shut, now the glove box drops down and drops out of place. it does not have the soft open action any more, it just drops down and i have to refit it if i forget to hold it, if you find the solution please let me know as i have been living wit the problem for about 6 months and dont fancy buying a new glovebox.
****** just read the tread above, ill be at mercedes first thing tomorow getting that part! thanks******
hopefully an end to a thorn in my side!