Screen lockups in Brave Dev (that last several minutes)

macos

#1

From time to time my Mac computer locks up without warning, and a blank grey screen appears for an extended period of time, during which no operations seem to be possible (no response to keypresses or mouse).

Eventually (usually takes at least several minutes), the display returns to what it had been & things seem to be back to normal. However, many tabs, when first accessed after this occurs, then also display a blank gray screen & have to be manually reloaded.

Most of the time no applications have crashed. As of the latest occurrence, Activity Monitor was “not responding”. But when I clicked on its Dock icon it re-opened normally. Not sure why any Activity Monitor issue would cause interruptions in Brave anyway.

What might be causing this?

(This is in Brave Dev, not sure about Brave Core)