Outlook Inconsistency Flummoxes Me

Inside my Outlook (Office 365), I have two different email address in use.  One one of them (my personal email), after I click on and open a new message in the inbox, the font and the messages changes to show that it's been opened, which is exactly what I want.

On the OTHER email address inside of Outlook, which represents the school where I teach, I CANNOT get the font/typeface to change after I open an message.  It remains the way it looked before I opened it up.  It's NOT a big deal but maybe it is because this inconsistency is kinda driving me crazy.

Might anybody know how to rectify this minor situation?

Thanks for reading!

Syd Rabin