How to reproduce:
1. Extract the attached project to your preferred Perforce workspace and open it
2. Connect it to Perforce
3. Submit the Assets folder
4. Go to "Test" -> "AssetList" to use Provider.Submit on the Scene.unity asset

Expected result: an error is thrown that there are no checked out files in the given asset list and Perforce remains connected
Actual result: a "No files to submit" error is thrown and Perforce disconnects

Reproduced in: 2019.3.0a12, 2019.2.1f1, 2019.1.14f1, 2018.4.6f1, 2017.4.31f1

Note: This occurs when any of the assets in the list are not checked. For example: if there's 1 asset that is checked out and 1 asset that isn't in the asset list, Perforce will still disconnect on Provider.Submit