Returned batches - Web Indexing

In the Indexing reports, there is a column titled Returned Batches.

Is that number
(a) The number of batches that the system has returned because they were indexed incorrectly (for example, submitting batches with incomplete or bad entries), or

(b) the number of batches that I found difficult to index so I went back to choose another batch, or a batch I was indexing but did not finish (logged out, for example)?


Attachment for sample

I thought I read somewhere that is (a), but I don't know that for a fact. Hopefully someone visiting the forum will know for sure as that is a question I have had as well.

Keep in mind that "indexed incorrectly" is a subjective term. I have seen situations where correctly indexed records are made incorrect by reviewers who are not careful (back in the days when you could actually see the arbitrator's changes to your indexed record). Both activities are subject to human error.