EP Core, pg 124 wrote:

APTITUDE MAXIMUMS Every morph has an aptitude maximum, sometimes modified by traits. This maximum represents the highest value at which the character may use that aptitude while inhabiting that morph, reflecting an inherent limitation in some morphs. If a character’s aptitude (including any bonuses from that morph) exceeds the aptitude maximum of their morph, they must use it at the maximum value for the duration of the time they remain in that morph. This may also affect the skills linked to that aptitude, which must be modified appropriately. Some implants, gear, psi, and other factors may modify a character’s natural aptitudes. These augmented values may exceed a morph’s aptitude maximums, as they represent external factors boosting the morph’s ability. No aptitude, however, augmented or not, may ever exceed a value of 40. Innate ability only takes a person so far—after that point, actual skill is what counts.