How to reproduce:
1. Open the user-submitted project ("EventSystem Creation Errors.zip")
2. In the Project Window click on the "StandaloneInputModule" object and observe the Submit and Cancel button fields being different from the default (You should see "SecondarySubm" and "SecondaryCanc")
3. In the Hierarchy create a new empty object, add an event system to it and click "Add Default Input Modules"
4. Observe the added module's Submit and Cancel button fields again

Expected result: the fields are the same as the "StandaloneInputModule" file in the Project Window as it is set to be the default (You should see "SecondarySubm" and "SecondaryCanc")
Actual result: the fields are not the same, they are "Submit" and "Cancel" instead. These are default Unity values, not the default set by the user.

Reproduced in: 2019.3.0a6, 2019.2.0b6, 2019.1.7f1, 2018.4.2f1
Couldn't test with: 2017.4.28f1

Note: The correct default module is added when adding the component manually through the "Add Component" button. The issue only reproduces with the Event System's "Add Default Input Modules" button.