Not failing native unit test assertions

I realized that some of my native C++ Unit Tests (using CppUnitTest) in Visual Studio worked incorrectly. It turns out that the assertions do not work for 32 bit but do work for 64 bit. I have checked the configuration of the project and both platforms are being build using the Debug configuration. Does anybody has a clue what is preventing the 32-bit platform from throwing exception when the assertion fails?. Checked the entire project configuration already and there seems not to be much difference between x64/x86..