Answer

According to Śvetāmbara doctrine, if a soul falls from the 11th guṇasthāna, it can rise again only by once more progressing through the spiritual stages and re-entering the higher path. The 11th stage is temporary; when the suppression of moha ends, the soul falls to a lower stage and may climb again if the conditions for purification are present. ( jainworld.jainworld.com)

Explanation

The 11th guṇasthāna is called Upaśānta Moha. In this stage, delusion is only suppressed, not destroyed, so the fall is possible when that suppression ends. Śvetāmbara texts explain that the soul may drop back to lower guṇasthānas and later rise again through further spiritual effort. ( jainworld.jainworld.com)

A key doctrinal point is that the upaśama-śreṇī can be ascended only twice in one lifetime. If it has been ascended twice, liberation in that birth is not possible. If it has been ascended only once, there is still the chance, after the fall, to reach the kṣapaka-śreṇī, which leads to nirvāṇa. ( jainworld.jainworld.com)

Spiritual Understanding

This teaches an important Jain principle: suppression is not the same as destruction. In the 11th stage, passion is quieted, but not fully uprooted, so a fall is still possible. Real permanence comes only from complete destruction of moha, which is the 12th guṇasthāna, Kṣīṇa Moha. ( jainqq.org)

Takeaway

So, in Śvetāmbara scriptures, a soul fallen from the 11th guṇasthāna can rise again after regaining the necessary spiritual purity and re-ascending the path. But if the upaśama-śreṇī has already been entered twice in that life, mokṣa in that birth is no longer possible. ( jainworld.jainworld.com)