Several of the basic ACOT psionic techs (like the psi altar) specifically require the Mind Over Matter ascension perk as a prerequisite. The Teachers of the Shroud origin, however, acts as a substitute for this perk - if you have the origin you can jump right to transcendence and indeed can't pick Mind over Matter at all, so these techs will never show up for a psionic empire with this origin. This can be easily fixed by switching the requirement to transcendence (what empire is researching ACOT techs without finishing their ascension path anyway?) or checking for either the perk or the origin.