Brief Summary
If I open private window and login into a website, then I should be logged into that website on other private tabs too.
Details:
So this is basically a carry from Safari. All other browsers share session info across tabs in private windows. In Chrome, Firefox etc., if you login into a website, e.g., Reddit, in one tab in a private window, then you remain logged into other tabs in the private window too. However, Safari (and by inheritance Orion) does not follow this. In Orion, logins/session information is not shared across tabs. So let's say I am browsing Reddit in a private window and want to open another tab to do a search, I would need to login again in this new private tab instead of sharing the session across tabs.
This isn't a bug but a design choice by Apple that I personally don't like. I am sure there are people who see benefit in this approach. However, Chrome, Firefox etc. they all follow the other approach. I think this might be Apple just trying to be Apple and "being different" just for the sake of it.
Also not sure how easy/hard it is to manage this.