Issue seems to relate to this comment;
#94 (comment)
Creating a new ticket as I cannot reproduce using the browser back button.

This bug is reproducible in the vanilla example for coexisting angular micro-frontends found here:
https://github.com/joeldenning/coexisting-angular-microfrontends

Reproduction steps;
Using the navigation app, trigger a route change, and then quickly trigger another nav change.

Issue is reproducible on;
IE11 (Very common)
Firefox (Mediocre-Hard)
Chrome (Rare)

Notes;
In our application we have found that having more simultaneous angular apps running in parallel triggers the issue more commonly, however this bug is reproducible with only one app actively loaded by the single-spa (however with difficultly even in IE11). (Issue does not occur at all with the app running in angular standalone without the spa)

The issue appears to be also related to Router.forRoot in some way, upon removing this from an app, the issue becomes more difficult to reproduce even with IE11, a similar effect to whether the app wasn't running.

This seems to be related to the speed of the navigation. Navigating twice very quickly causes this effect.

If struggling to reproduce, we found that having a button which changes to swap between two pages and spam clicking it causes the bug to reproduce on IE11 every time.

The navigations do not need to be between separate apps, routing between two pages on the same app causes the issue.