This issue was fixed on master by SERVER-50778. In 4.4 and order versions, the array updates were done lexicographically on the index keys. So an array value at index 10 would have been updated ahead of say index 3. If there was an array no value at index 10, we would have create array entries with 'null' values upto index 9. Because of the missing field semantics, we would just update the value in $min for index 10. When we try to update index 3 next, there will be a 'null' value. Since the 'null' value is considered less than any other BSON element, we would not update the value for index 3. If the update system had started with index 3 instead, we would have updated both index value 3 and 10.