I think this is a service issue...
If you wait until the tensioner gets really bad(or maybe not torqued correctly), the cover is damaged. The angle imparts a load that is prying on the cover as the tenioner fails.
I believe the 601 tensioners ussually last 75-100k.
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD