Fullscreen on multiple displays and swiping moves all screens

This worked up until May 16th. Before and after updating to macOS Sierra 10.12.5 did not solve problem.

Config / Specs:

• MacBook Pro
• Dell monitor
• iPad using Duet app

Previous functionality

I could expand fullscreen any app/program in Mac (the green button top right) and use 3 fingers on the trackpad to toggle between 'screens' on that individual physical screen.

Current bug

When I fullscreen an app on one display and swipe with three fingers, swiping controls all 3 physical displays. The display in question swipes to the app, but the other two displays also swipe to the right showing blank black or white backgrounds and are mouseover-able.

Desired functionality -- the Previous Functionality

Swiping on a screen only controls that display.

Solution 1:

System Preferences → Mission Control and enable Displays have separate Spaces.