Using Outlook 2016, focusing or reading a message and pressing CTRL+R, CTRL+E, CTRL+L, etc. NVDA says "Left aligned". This is not a trivial issue, but I wanted to update it with my results.

I can also reproduce this with UIA enabled in Outlook 2016.

I can reproduce it now with NVDA alpha-17611,7b2861fc and both Outlook 2010 and Outlook 365. In my case, NVDA reports left aligned. I think Outlook expoeses the information via UIA or the accessibility API even when reading messages. If the text in the message is centered, NVDA will report that instead. The same for right aligned.
I think it will be really hard to filter out this reporting for reading messages. Ideally Microsoft should change the behavior in such a way that Outlook exposes this information only when composing, forwarding or replying to emails.