Paging On compound index

Working with Data
1

I have some large collections with documents like this:

{
   _id : snowflake,
   field1: NumberLong
   field2: NumberLong
   field3: NumberLong
   field4: NumberLong,
   value1: string
   value2: double
}

This collection has 3 indexes:

id on the _id field
indexA_unique has {field1:1, field2:1, field3:1, field4:1}
indexB has {field1:1, field2:1, field3:1, field4:1, value1:1, value2:1} This index is also unique.

I am trying to read the collection in batches (using DBCursor). The query includes all fields except _id as a “fields projection”. If after reading n records, someone inserts a record that will fall in position n-m according to indexB (which I assume will be used by the DB for this query), could the next batch of records include a previously seen result?