the attachment of the dust boot is always a compromise.
Either you attach it to the Z assembly/X gantry, and you adjust it to your workpiece height, but it is also possible to
use a dust boot that attaches to the router/spindle. It will move up and down with the router or spindle. But this has disadvantages too. Imagine you want to mill a deep pocket into your workpiece. You see?
Same. I was getting bristles blocking the opening. Just gave the mustache a quick trim and it seemed to have solved the problem in my case as well. I still want to get a different dust boot, but not quite ready to do that just yet.