In the above-mentioned paper by T.-T. Lee and S.-H. Lee [ibid. 31, 958-962 (1986; Zbl 0596.93023)], the derived perturbation bound for the stability of a linear optimal system is incorrect. The source of the error is identified and a corrected result is given. Furthermore, it is pointed out that an even more fundamental problem exists before the derivation process is started. A remedy is suggested.