Scroll lag when laptop not plugged in

If my laptop is unplugged, and I’m inactive for 10s or more, then when I try to scroll (using mouse scroll wheel, or up/down arrows, or touchpad) the scroll doesn’t happen for about 1s. It then continues as expected. That is, after the 1s pause scrolling then works smoothly. But if there’s another inactivity period of 10s or more, then the next scroll will wait for 1s before scrolling.

Just moving the mouse doesn’t help. That is, if I wait for 10s, then move the mouse, then try to scroll, I still get the 1s pause before scrolling begins.

The problem is unaffected by Power settings (Brave Power - Energy saver) and Memory saver settings.

  1. Unplug laptop
  2. Go to any page in the Brave browser that is long enough to be scrolled
  3. Do nothing for 10s (no kb, no mouse, etc.)
  4. Scroll up/down (using bouse wheel, or up/down arrow).

Expected result:
I expect the page to scroll. But instead it waits for approx. 1s, and only then scrolls. Subsequent scroll attempts (within 10s of the previous scroll) scroll immediately, without the 1s pause.

Brave Version( check About Brave):
Brave is up to date

Version 1.58.127 Chromium: 117.0.5938.88 (Official Build) (64-bit)

Additional Information:
This doesn’t happen on Chrome and Edge browsers. With these browsers I can pause for many seconds, and then when I try to scroll it scrolls immediately.

Also, if I plug the laptop in, the problem disappears.