The paper presents the discussion of the interaction of two electrostatic waves, propagating in a homogeneous magnetized plasma, with ions. The same case for two and three waves was already discussed in the paper of Misguich and Nakach [Phys. Rev. A, Vol. 44 (1991) 3869]. Contrary to their paper, we solve the dynamics not in the drift approximation, but in a full solution, using the Hamiltonian, which includes also a cyclotron motion of particles. We show that in a realistic regime, the full solution can cause stochastization of the dynamics in cases, when the drift approximation permits only regular dynamics.