In a multimode industrial control system (ICS), mode switching decisions have to follow standard operating procedures which are set for the safety of the system based on the operating limitations of equipment. A rich literature can be found on monitoring multimode systems. However, that work is mainly focused on mode identification and monitoring anomalies in the process running under each mode. Instead, we present a data-driven method for monitoring the modes' switching constraints. This work is based on state-transition matrix and decision-tree methods to discover data-driven mode switching conditions. However, our approach is not limited to only threshold based condition learning. To capture data trajectory based conditions we adopt functional data descriptors method. In practical experiments, we showed that our approach can discover anomalous mode switching decisions which can't be discovered by previous multimode process monitoring methods.