How to reproduce:
1. Open user-submitted project (undo bug.zip)
2. Right-click the Project window and select Create > My Asset
3. Open this asset via a Text Editor, note that myList is empty
4. In the Editor, select the asset and click 'Add Entry with Undo' or 'Add Entry with Complete Undo'
5. Select File > Save Project
6. Open the Asset in the Text Editor again

Expected result: myList has been updated
Actual result: myList is still empty; restarting the Editor would cause the loss of this data

Reproducible with: 2017.4.40f1, 2018.4.22f1, 2019.3.11f1, 2020.1.0b8, 2020.2.0a8

Notes:
Using the 'Add Entry with Undo and SetDirty' option dirties the Asset correctly and saves changes