All newly created "Sorting Layers" share the exacts same name under "Tag and Layers" Settings from Project Settings window, Refer to the attached screenshot.

Steps to repro:
1. Create a new project
2. Edit > Project Settings > Tag and Layers > Sorting Layers
3. Add new (+) more than 3 Sorting Layers in the List

Actual Result:
Sorting Layers are created with the same name

Expected Result:
Sorting Layers should be created with a different name as Layer 1, Layer 2, Layer 3, and so on

Occurring on:
2020.2.0a20, 2020.1.1f1, 2019.4.7f1, 2019.3.15f1, 2019.2.13f1, 2019.1.11f1, 2018.4.24f1

Environment:
Windows 10 and Mac 10.14