Mantras are only endowed with transformative electricity if offered in initiation (dīkṣa) within the mouth of a Expert. It is far from much correct pronunciation, but somewhat the power with which the mantra is endowed that provides it reworking functionality. Cundī dhāraṇī or mantra also first appeared in the Kāraṇḍavyūhasūtra: https://shani76653.blue-blogs.com/44455529/yantra-no-further-a-mystery