The apparent yield strength anomaly in the B2 YCu intermetallic compound is shown not to be a yield point anomaly at all, but rather a phenomenon resulting from the work hardening behavior in YCu, which was found to rise with rising temperature and to drop with increases in strain rate. This effect is shown to occur over temperature ranges where YCu has negative strain rate sensitivity, result in dynamic strain ageing behavior, and the effect is shown to be irreversible when the testing temperature is changed. Neutron diffraction experiments utilizing SMARTS and HIPPO show the evolution of texture and the change in plastic deformation behavior as the temperature is raised.