Firstly, thank you for the great plugin!
I just installed simple:press v 5.0.5 and everything seemed to be going swimmingly until I attempted to view the forum page as a guest. I could see the forum page but it was acting like an image. None of the links or boxes worked and nothing was identified. I finally noticed that printed at the bottom of the page was "Powered by @TheFrosty". I turned the custom login plugin off and now everything works fine.
For some reason the custom login plugin seems to be treating the guest forum page like a login page (but without the login script). I really like having control over the appearance of the login screen. Do you have any insight into why the two plugins are not getting along?
Also, the problem does not manifest in IE. So far i have seen it in Firefox and the WebOS browser on my phone and touchpad. I haven't had a chance to test with safari or chrome yet.
I will leave the custom login plug-in active for the time being so you can see how it is acting on my site > http://www.contradigmcomics.com
Thanks for your help!