Hi and welcome back avast forum!
A user have reported to me and I can confirm this bug with avast 9.0.2018 (tried on free and IS):
If you have an item added in the global exclusion and then go into the file system shield, under the exclusion, you can see a label “This component is also applying global exclusion you can check them here”.
Now if you click on the link you can see a blank black page, instead the global exclusion page, see attached.
Also confirmed.