How to reproduce:
1. Open user-submitted project (ProgressBarProblem.zip)
2. Reset the Editor Layout to Default
3. In the Menu bar select Examples > Progress Bar Usage
4. Dock the window
5. Click 'Display bar'
6. While the progress bar is shown, snap the whole Unity Editor window to the side of the monitor

Expected result: no assertions are thrown
Actual result: Assertion failed on expression: 'device.IsInsideFrame()' error is thrown

Reproducible with: 2020.1.15f1, 2020.2.0b12, 2020.2.0b13, 2021.1.0a4, 2021.1.0a7
Not reproducible with: 2018.4.29f1, 2019.4.15f1, 2020.1.0a22
Could not test with: 2020.1.0a23, 2020.1.14f1, 2020.2.0a1, 2020.2.0b11, 2021.1.0a1, 2021.1.0a3(script does not invoke a progress bar at all)

Notes:
Alternative reproduction steps: open the project, use the same menu option to invoke a progress bar and close the Editor while it's in progress. Upon reopening the project the same assertion will be thrown
Script is borrowed from the DisplayProgressBar manual page of 2019.4 manual