The central result in the optimal control theory is the traditional criterion of the optimum existence which leads to the convexity and the compactness of the system contingent set. However this principle is not universal. It is found that the traditional criterion of the optimal control existence violates for control semilinear systems describing by hyperbolic equations and some functionals. It is demonstrated by three examples that the analog of the traditional criterion for the optimal control existence is not true for a certain class of distributed control systems.