I do not know the full reason why, but since 04/08/2019 the brave browser adblocker hasn't been working at all. This has really given a small shitstorm on the community forums of brave browser where people are trying to figure out why they are getting ads while the script blocker is active when they are on youtube or other sites.
This is not a problem that only happens with google advertisings but an all-over problem with any adnet since I have been testing it on my own website that is running both adaround and A-ads and both of them were still showing.
I think at this time that there has been a browser update that has broken the script or software that is supposed to block the advertisings and scripts.
Don't worry this won't hurt you at all and if you have been thinking of downloading brave then stop thinking and click here to start downloading it!
We just have to live with the script blocker not working to the fix is done.