I was so shocked on reading verse 30 of Judges of 18 that I consulted close to ten Bible Commentaries to see if indeed the idolater priest that the verse mentioned was indeed the grandson of Moses. "There the Danites set up for themselves the idol, and Jonathan son of Gershom, the son of Moses, and his sons were priests for the tribe of Dan until the time of the captivity of the land. ³¹ They continued to use the idol Micah had made, all the time the house of God was in Shiloh.(NIV translation)"  "Then the children of Dan set up for themselves the carved image; and Jonathan the son of Gershom, the son of Manasseh, and his sons were priests to the tribe of Dan until the day of the captivity of the land." (NKJV translation)

Most of the Commentaries opine that the translation with the name Manasseh came about because the Jewish scribes by respect for Moses added one letter to the name to change it from Moses to Manasseh who was  a wicked king in the future of Israel. It is indeed great sadness when the subsequent generations of a man of God fall into idolatry. 

Please read Judges 17 - 19. And Listen.

May the Lord richly bless you!