Hi Walles,
index3.html is called from login.js that handles the login. At least, that's what I think it does. I just came across the index3.html.
I think index3.html is opened if the system can't find an index.html. In my case, I changed the name of index.html that lead to the behaviour you describe.
Could that be the case, a missing index.html file from your ../deployment/web directory?
Cheers. Toon