isDebugBuild returns False in the Editor when its value is checked after a build

How to reproduce:
1. Open the attached project "Case_1317834"
2. Build the project
3. Observe the Console Window

Expected result: isDebugBuild returns True
Actual result: isDebugBuild returns False

Reproducible with: 2018.4.32f1, 2019.4.22f1, 2020.3.0f1, 2021.1.0b11, 2021.2.0a8

Notes:

• Restarting the Editor resets isDebugBuild to True
• Screenshot is attached of the Console output showing isDebugBuild being false