MultipleErrorsOccurredInfo does not implement parse(), because it is not intended to be a general purpose error info, and at the time of its implementation was never used between nodes within a cluster. However, after SPM-3209, mongos may forward multi writes to the db primary shard for dispatch, with the db primary shard transparently returning whatever response it receives back to mongos. In this case, mongos should be able to parse the MultipleErrorsOccurredInfo returned from the db primary shard so that it can be handled properly.