Custom Case class Slick.scala

case class AuditResultLightLifted(
  ProcessorId: Rep[Long],
  DispatchedTimestamp: Rep[Timestamp],
  IsSuccessful: Rep[Boolean],
  AuditResultId: Rep[Long]
)

case class AuditResultLight(
  ProcessorId: Long,
  DispatchedTimestamp: Timestamp,
  IsSuccessful: Boolean,
  AuditResultId: Long = 0L
)

implicit object AuditResultLightShape 
  extends CaseClassShape(AuditResultLightLifted.tupled, AuditResultLight.tupled)
  
class AuditResultTable(tag: Tag) extends Table[AuditResult](tag, AuditResultTableName) {
    def auditResultId: Rep[Long] = column[Long]("AuditResultId", O.PrimaryKey, O.AutoInc)
    def processorId: Rep[Long] = column[Long]("ProcessorId")
    def dispatchedTimestamp: Rep[Timestamp] = column[Timestamp]("DispatchedTimestamp", O.SqlType("timestamp(2)"))
    def SystemAOutput: Rep[Array[Byte]] = column[Array[Byte]]("SystemAOutput", O.SqlType("LONGBLOB"))
    def SystemBOutput: Rep[Array[Byte]]  = column[Array[Byte]]("SystemBOutput", O.SqlType("LONGBLOB"))
    def isSuccessful: Rep[Boolean] = column[Boolean]("IsSuccessful")


def * : ProvenShape[AuditResult] = (processorId, dispatchedTimestamp, systemAOutput, systemBOutput, isSuccessful, auditResultId) <>
  (AuditResult.tupled, AuditResult.unapply) 
}  

val auditResults = TableQuery[AuditResultTable]  
val auditResultsLight = auditResults.map(r => AuditResultLightLifted(r.ProcessorId, r.DispatchedTimestamp, r.IsSuccessful, r.AuditResultId))  


def getRecentFailedAuditsQuery(): Query[AuditResultTable, AuditResultLight, Seq] = {
  auditResultsLight.filterNot(r => r.isSuccessful)
}

Good point, @Raffaello. Done!