Please see next reply. Thank you.
Back arrow often not available within tab
ElenaHaskins
#2
Yes, I want to give you the Brave version number and when I try to get it a 404 shows.
It is probably the most recent version.
Frequently, when linking to another site the referral page is no longer available by using the back arrow.
OS X El Capitan Version 10.11.6
Mac mini (Late 2009)
At Your Convenience, you may want to check into the Mystery of the Disappearance of the Back Button. 
sriram
#3
This issue has been captured and can be tracked here
The feature of navigating back using the backspace was removed intentionally.