Thanks, just tried it and I can confirm this is fixed.

On Mon, Aug 9, 2021 at 7:15 AM Alan Third <alan@idiocy.org> wrote:
On Wed, Feb 10, 2021 at 09:50:03AM +1100, Li Feng wrote:
> I tested emacs master on a retina display, and it is all good. fringe icons
> are rendered correctly on both internal and external displays. However, on
> low-res external displays the fringe icon rendering is still broken.

I've completely rewritten the fringe bitmap display on the master
branch. Can you please have a look and see if this is still a problem
for you?
--
Alan Third