Could you attach a copy of your DisplayFusion troubleshooting info?

• Open the Settings > Troubleshooting tab
• Click the "Export Info to File" button
• Reply with the file attached

Ah yep, sorry about that! So, the reason for that gap is because the monitors are different scaling levels. When DisplayFusion calls the Windows API to set a window position, the top-left corner is actually about 7px to the left of what you can actually see on the window, because Windows 10 makes the borders invisible.

Normally what we do is move the window over by 7px, but because of the scaling difference, if we do that, it hangs on the other monitor and Windows returns the wrong scaling level

Yeah, personally I would just leave it as is for now. I use different scaling levels here, and having to change those would be more disruptive (for me anyway) than dealing with the gap.

We also may be able to fix that gap on the right-side of the left monitor, I've put that on our list to investigate, as this behaviour should only actually affect the left edges of windows.