Does it happen in safe mode? As it’s the login screen, you may need to manually append this to your site address - [YourSite]/login?safe_mode=no_themes%2Cno_plugins
I also cannot reproduce this issue. I’m on a slightly more current version - 3.4.0.beta1-dev (32195ed77e)
A couple of basics to help narrow it down - is this a standard install? And what plugins and/or theme components do you have installed?