Using classic Outlook for Windows in business environments
TY to OP, as this clearly shows a problem the majority of us have with the UI layout. Please, IF YOU ARE READING THIS, write feedback as explained throughout the thread, that this change was something you DO NOT LIKE. Select, copy, and paste this thread's title, which will make it that much easier to leave feedback. This change needs to be made optional or reverted permanently.
It doesn't happen until you have a new sign-in, as I was researching an email claiming there was a breach attempt on my account and suspected the email to be a phishing attempt. When I signed in through, https://account.live.com/Activity to look at my activity, it triggered this change on my account's email.
The correction to this change of the UI layout will not happen, unless everyone who is unhappy with it, leaves feedback.
Also, if the change was triggered by a new sign-in, it may take another new sign-in after it is corrected to revert. Hopefully, M$ at least includes the ability to revert or choose the column alignment that suits the user best.