Disabled views Displays causing error message in Views UI / caused by ajax error

Can you reproduce this with just core?

I tried and couldn't with the provided information. What I tried:
* On a clean Umami install
* Go to the content view
* Duplicate the page display and give the new display a new route
* Save the View
* Disable the new display
* Save the View
* Click around the View UI => no problems

So not sure what the issue is, but it's not just having a disabled View with a route, it seems to need more to break

I do not know if it breaks in core. I have seen the issue in calendar module and this is 100% reproducible.

I think I have a similar issue with the following steps to reproduce.

1. Create view as a Page
2. Set Page path
3. Save view
4. Add page into a menu
5. Open the view and disable the Page
6. Save view

Result is "Oops, something went wrong. Check your browser's developer console for more details. " When looking at the browser

Uncaught TypeError: document.querySelector(...) is null
    g https://example.com/admin/structure/views/view/testviewname/edit/page_1 line 827 > injectedScript:3
page_1 line 827 > injectedScript:3:79

and

Uncaught 
Object { message: "\nAn AJAX HTTP error occurred.\nHTTP Result Code: 500\nDebugging information follows.\nPath: /admin/structure/views/view/testviewname/preview/page_1\nStatusText: error\nResponseText: The website encountered an unexpected error. Try again later.", name: "AjaxError", stack: "@https://example.com/core/misc/ajax.js?v=10.4.1:196:32\n@https://example.com/core/misc/ajax.js?v=10.4.1:1935:3\n" }

Changes are made on on 11.x (our main development branch) first, and are then back ported as needed according to the Core change policies → .