Proxy Problem with Outlook Plugins

Is anyone aware of a way to remove specific re-writes of the URLs or some way around the issue below without disabling the proxy?

Full Story: 

We are integrating a plugin to Outlook (Third-Party) and the URL is being re-written on POST from  https://login.microsoft.com/commonto https://thecas (not literally, but you know what I mean). The only working resolution is to completely remove the proxy from all Office365 apps.

Note: 

Excluding the plugins enterprise app, app registrations, etc. have no impact on the rewrite. It appears Outlook has the final say with web-based plugins on conditional app policy/cloud proxy.