Configuring preferences and options in Outlook.com
Those are definitely weird symptoms. Is only Outlook affected or do you see similar weird behavior in Word?
Have you tried a repair yet? To repair your Office installation, right click on the start menu and choose Apps & Features, find and select the Office installation. Choose Modify then select the Quick repair option. Use the Quick Repair option first as it will fix many things and complete fairly quickly.
If it doesn't help, use the Online Repair option to uninstall Office and reinstall Office. It will not delete your existing Office settings or your Outlook profile and data files.