There is a shared .props file that is used by the various ICU library components to set common/shared settings like "no exceptions", and various warnings configurations.
However, this file currently ignores any preprocessor defines that are set on the command line using MSBUILD.
This unfortunately breaks some scenarios where various flags need to be set using MSBUILD.
The fix is a one line change to add $(DefineConstants); to the file.
See the link below for the change: