I have tried to find what is causing this and I am at a loss, here is how you duplicate the problem.
Log into ContentBox
Restart ColdFusion or change the App name
Click on any link, and log back in.
The redirection will then look like this
It looks like when the previous URL is captured it is not caring if it is a rewrite rule or not, I have done a search for this but it looks like it is bypassing the rewrite rules somehow. I just can’t seem to see how.
But rest assured it is there and extremely easy to duplicate.