[BUG] Build won’t start with certain scripting define symbols, with no error shown

I’m using Steamworks.NET 20.2.0, installed through Unity Package Manager. With DISABLESTEAMWORKS defined and STEAMWORKS_NET absent, I couldn’t start a build. No failed Upload Task appeared, and no errors were shown in the Unity Console.
Adding STEAMWORKS_NET allowed the build to start, even though I intended to disable Steamworks for that build.

To Reproduce

1. Use a configuration with DISABLESTEAMWORKS defined and STEAMWORKS_NET absent.
2. Attempt to start a build through Build Uploader.
3. In my case, the build does not start, with no failed Upload Task or Unity Console error.
4. Add STEAMWORKS_NET and try again—the build starts.

Expected behavior
The build should start, or an error should explain why it cannot start if the scripting define configuration is invalid.

Environment

• Unity: 6000.3.24f1
• Build Uploader: 3.3.0
• OS: Windows 11
• Steam plugin: Steamworks.NET 20.2.0 (UPM Git package)

Additional context
I’m unsure what caused this or whether it relates to STEAMWORKS_NET being added automatically. I’d be happy to investigate further or test potential fixes.