I just downloaded Brave, and was able to login with it on bitcointalk just fine. (I was even using a VPN, but no extensions!) So, no, works fine here.
(All the default shield settings are up too!)
Brave is up to date
Version 0.55.18 Chromium: 70.0.3538.67 (Official Build) (64-bit)
Thanks for taking the effort to test it out yourself though. Looks like the problem is only on my side.
EDIT: A quick clear of cookies did the trick lol. should've tried this from the start.
My conclusion: there probably was a problem when I imported my browser data from Firefox to Brave, hence the problem with the cookies. Probably an incompatibility or something. Problem is not on bitcointalk's side.