Answer

Neminath Bhagwan’s Moksh Kalyanak is generally observed on Ashadh Shukla 8 / Ashadh Sud 8. Some Jain sources also mention Ashadh Krishna 8, so it is best to follow the specific Jain panchang or temple calendar used in your tradition. ( jainworld.jainworld.com)

Explanation

The most commonly listed date in Jain references is Ashadh Sud 8. However, because a few published sources record it differently, there can be variation in how the date is written. ( jainworld.jainworld.com)

Takeaway

If you need the date for a puja or calendar, use the local Jain calendar/panchang followed by your sangh or temple.