View password icon on Safari is sometimes black rectangle

The view password icon is not visible in the Safari browser (v.17.6). It is displayed as a small black rectangle. In other browsers, everything works fine.

I didn’t find a reliable way to reproduce this issue in every scenario. It happens while viewing the login page, say 1 out of 8 times.

There are no errors in the console or the network tab.

The only strange thing I noticed is this:
When this issue happens and I see a black rectangle in place of the eye icon I can go to:

  1. Network tab
  2. Request of given icon from auth0 → data:image/svg+xml;base64,PHN…
  3. Headers tab of request
  4. There is no content in Request/Response headers. Also, there is no info about Status or Source.

The only slightly related topic I found about a similar issue is here - Blank Squares - Occasional problem in Safari (iOS) · Issue #7770 · FortAwesome/Font-Awesome · GitHub

Any ideas about what might be the cause here, or how to fix it?