Mostly these would be cases where the browser would, seemingly at random, end up in an unpredictable state and all proceeding test scenarios would fail because

Mostly these would be cases where the browser would, seemingly at random, end up in an unpredictable state and all proceeding test scenarios would fail because of this. (Page is white, or a completely unrelated website gets opened. We have seen lots of weird situations so far) This might be exacerbated by the fact that we use the remote Browserstack Selenium hosting service so that the tests can be executed automatically as a part of our deployment process.