Safari unpredictably stalls loading crossorigin resources (CORS bug?)

We're hitting an issue where Safari on Mac renders a page fine for a period of time but then, for unknown reasons, fails to load some resources stored on a different (unauthenticated) subdomain if 'crossorigin="anonymous"' is specified.

These are the same resources (css, js) that had been loaded fine earlier in the session. The hosting of the resources is consistent.

Safari doesn't produce any errors, it just hangs forever appearing to request the resources. We believe this is a CORS related issue for a couple of reasons.
  1. This only happens to resources that are loaded with 'crossorigin="anonymous"'

  2. Once Safari is in a broken state, the toggling on "Disable Cross-Origin Restrictions" will let the page load, and toggling it off again will return it to the broken state.

The only other way to fix the browser session is to quit and restart Safari.

I've logged a Safari bug/feedback but haven't heard anything back.

Does anyone have any idea how to solve this without removing the crossorigin parameter from these resources? Any Idea what else might be triggering this behaviour? Users are logged in at this point so there are various cookies set.

Understandably, not all users want to switch to Chrome.