[ABANDONED] emBuild not executing pre-build step defined in project file

I have an SES project that uses a pre-build step to generate a header file used later in the build. I also have a Docker container intended for CI builds so that I can use emBuild to build the code on any host OS. If I use the container on Windows, the pre-build step is executed. If I use the container on a CI machine, the pre-build step is not executed, and the build fails (because the expected header is missing). The emBuild invocation is identical in both cases:

/usr/local/ses/bin/emBuild -rebuild -verbose \
   -config "Debug (extra words)" \
   myproject.emProject

emBuild fails in interesting ways when run non-interactively from the container, for example:

+ /usr/local/ses/bin/emBuild -rebuild -verbose -echo -config Debug_E4_BLE -solution Banana banana.emProject
1>Building Library from project 'application' in configuration 'Debug_E4_BLE'
1>/usr/local/ses/bin/emBuild /usr/local/ses/source/arm_segger_studio_auto.emProject -config V7EM FPv4-SP-D16 THUMB LE Hard Balanced WCHAR32 EnumMinSize Release -project all -lock /usr/local/ses/lib/build.lck
4>Compiling 'battery.cpp' from project 'application' in configuration 'Debug_E4_BLE'

It's not clear why emBuild is trying to build a Library or why it is running another emBuild instance.

Does anyone have some experience with this kind of problem?

Thanks in advance,
-Adam