3100cn envelope wrinkling problem

Has anyone else had this problem?!?!  The 3100cn seems to wrinkle every envelope we put into it.  We tried heavier stock with the same result.  Otherwise, the printer seems fine.  Letter and legal printing works ok.  Legal from the MPF works ok, without wrinkles or extra bending.  Please, if anyone has seen this, let me know.

 

Thanks.