This mean that there are two or more benefits associated with this batch item, when there can only be one. This can most commonly happen during adjustment batches, where the membership benefit has already been delivered and a user does a benefit recalc from Batch summary. TA may add another membership benefit to the batch item(s) because they qualify for them, but it will not remove the existing membership benefit, because it is already been marked as delivered and thus cannot be removed.

The solution is to remove the newly added membership benefit from the batch, so there is only one membership benefit for the batch item.