The synthesis of carbodiimides via nitrene transfer to isocyanides has garnered significant attention in recent years. However, this reaction predominantly relies on homogeneous catalytic systems with high catalyst loadings. In this study, we employed ZIF-67 MOF as a heterogeneous catalyst for carbodiimide synthesis and conducted an in-depth analysis of its stability. Our findings reveal the non-innocent role of catalyst leaching, demonstrating that even as little as 0.04 mol% of leached cobalt species is sufficient to catalyze this reaction. This result is in contrast with previous reports, where 5-10 mol% of homogeneous cobalt-loading is required. Furthermore, this study highlights that lower catalyst loadings are more efficient, particularly in cases where isocyanides exhibit limited stability.