Not Amazon referral links. More like Firefox Suggest or the like: Write eg. "Binance" in the URL bar, and one of the results in the dropdown menu is a sponsored link to "binance.us" who are partnered with Brave. The feature had a bug that caused complete, valid URLs (ie. you wrote "binance.us") to be shown the sponsored link as a primary completion option.

The issue persisted, as far as I know, one day. The response was to both fix the bug and make the feature be off by default.