Vacuum Cleaners Discussions

Is is normal to find dust bypassing your vacuum bag? I've been using premium cloth "anti-allergy" bags (I believe that mean thicker cloth layers), and when I opened up my canister yesterday, I was a little surprised to find a thin layer of dust within the compartment. I inspected the cloth bag to see if there weren't any punctures from any sharp debris within, and didn't find any. I suppose that's why there is a pre filter in the compartment as well, but I was surprised to see the dust bypass after moving to a new place and vacuuming different carpet for the first time. I suppose a higher concentrated influx of dust and dirt from poorly maintained carpeting may be to blame for the noticeable bypasss.