Using New Outlook on Windows for personal email, calendar, and contact management
Unfortunately, I already had my work hours set correctly, and the problem was still happening. I did not have work hours set for Saturday and Sunday (since I don't work those days!) but I went ahead and added "fake" work hours for those days. We'll see if it solves the problem.
This is one of those absurdly frustrating things that makes me think, "**** - they're a multi-billion dollar company - don't they even try using this software before they release it?!?!?!" Then I calm down and remember that it's just a bunch of human beings in a big building somewhere doing their best.
Like other people have said, I may switch back to "old" Outlook until (if and when) I'm forced to use the new one.