[da Vinci Dan]

Did you put it on? The reason I ask is that i have noticed when I replace mine that it can sometimes not seat fully even after the L shaped retainers are locked down. It sometimes needs a slight shift / pressure / wiggle and then it fully clicks into place.

A misaligned cap may explain your problem. Bosch parts are usually pretty well made. However, I have had a few duds over the past couple or years. So, It may also be the case that their quality is declining.