Whenever I open the Facebook emoji box, the consumption of RAM and swap memory grows to the point where my system crashes completely.
This same feature - Facebook emoji box - is working correctly in the latest stable versions of Firefox and Vivaldi browsers.
My tests were made on the latest stable version of Brave Desktop and on Beta Version 1.38.67 Chromium: 100.0.4896.46 (Official Build) beta (64-bit).
For these tests, I used both Ubuntu MATE 20.04 and Kubuntu 21.10.