The color-appearance model CIECAM02 has several problems, which can result in mathematical instabilities, due to the relation of the chromatic-adaptation primaries to the spectrum locus and to the presumed physiological cone primaries. To keep a corresponding color within the positive gamut given by the chromatic adaptation primaries, that gamut must lie within the cone primary octant. To contain a color that is already outside the gamut, it suffices to algebraically prevent adaptation from moving a test color outside the positive octant of the physiological cone space. Such modifications may be needed to avoid the mathematical problems in CIECAM02.