Windows Defender Security Center

Refer to the attachment. Why is the real time protection turned on. I want to disable it, but it automatically turns back on. I even checked the task manager>Startup and it shows that Windows Defender Notification is disabled.

I have avast free installed. Fully up-to-date and Windows Creators Update fully up-to-date. Is this a bug from Microsoft?

This is what I see:

http://screencast-o-matic.com/screenshots/u/Lh/1493038703469-95672.png