Steps:

1. Go to Admin/Content Types/Content
2. Click Edit next to a Content Type
3. Click Save
4. Click back button in web browser

Actual result:

Error 404 is thrown: Could not find 'eZ\Publish\SPI\Persistence\Content\Type' with identifier 'ID: 45, Status: 1'

Expected result:

We can display more user friendly message. Or redirect user to somewhere else?