When TcUnit is running it allocates memory in the PLC to store the test results. The maximum number of tests for every test suite has been set to 100, which however is a configuration parameter for TcUnit and can be changed. Parameters for TcUnit (and in fact any library references) are stored in your project, which means that this change will be persistent for your project/library. To change this max amount, to say for instance 200 tests per test suite, go to the library references and select TcUnit, then go to GVLs → GVL_Param_TcUnit → MaxNumberOfTestsForEachTestSuite.
Required TcUnit version: 1.0 or later