Why is Angular component not loading on browser back/forward navigation?

Angular 7.2.13

When navigating with the browser back button, the HTML of the component is loaded, but the component css/js is not loaded, and the page hangs.

However loading works fine when navigated by a link click or router.navigateByUrl() or if the page is reloaded. But never when navigating with the forward/back button.

I'm getting no console errors.

It works perfectly on the development server http://localhost:4200/. This issue occurs only in production.

UPDATE

This is happening in a child route.

UPDATE 2

Can't replicate the issue in a stackblitz with the same route structure. https://angular-tpsr5z.stackblitz.io/.

UPDATE 3

After hanging like this the component will immediately load if I click anything that fires a component method, or changes a property of the component.

from Why is Angular component not loading on browser back/forward navigation?