Any software based on Chromium, including Brave, Vivaldi, and (strangely) Skype, exhibits this behavior. The fix I use is to add "--disable-gpu-sandbox" to the executable command line (Chromium.app/Contents/MacOS/Chromium --disable-gpu-sandbox).
(The cause is probably due to using a non-standard GPU in Mojave.)
On my system I made an app wrapper that does this. I've attached the one I use for Brave, and you just have to rename things and point the shell script in Contents/MacOS to the right executable. You can change the "app" icon by copying and pasting between two Finder Get Info panes.
HTH