Publishing a subset of changes(Partial Publish) from the Project Window when the Collab Window is closed opens up the Collab Window with the 'Publish' button disabled and throws the following error in the console,
"AssertionException: Assertion failure. Value was False Expected: True"

Steps to Reproduce:
1. Create a New Project
2. Edit > Project Settings > Services > Collaborate > Set Organization > Create Project ID
3. Project Settings > Services > Collaborate > ON
4. Project > Right-click > Create > Material
5. Collab Window > Close
6. Project > New Material > Right-click > Collaborate > Publish

Actual Result:
Publish button is disabled and the following error is displayed
"AssertionException: Assertion failure. Value was False Expected: True"

Expected Result:
Collab Window should open up without any errors and the 'Publish' button should be active

Workaround:
Deselecting the changes and reselecting them OR Opening Changes Panel from Project Settings > Services > Collaborate enables the 'Publish' button once again

Note:
The above-mentioned error only occurs in the 2020.1 stream, but the 'Publish' button remains disabled for both Streams viz. 2020.1 and 2020.2

Occurring in:
2020.2.0a16, 2020.1.0b14

Working Fine in:
2020.2.0a15, 2020.1.0b13, 2019.4.2f1, 2019.3.15f1

Environment:
Windows 10 and macOS 10.14

License type: Pro