Running a left outer join between a parent and child custom table in salesforce results in an error:

select a.id, a.name, a.LastModifiedDate, b.Order_Recipe_Steps__c, b.name
from MPRS_Salesforce.Media_Prep_Order_Recipe_Steps_c a left outer join "MPRS_Salesforce"."Recipe_Step_Detail_c" b
on (a.id = b.Order_Recipe_Steps__c)
where b.LastModifiedDate >= parsetimestamp('2016-05-04 15:01:03.0', 'yyyy-MM-dd hh:mm:ss.s')

Error: TEIID30504 Remote org.teiid.core.TeiidProcessingException: TEIID30504 MPRS_Salesforce: com.sforce.soap.partner.InvalidSObjectFault: INVALID_TYPE:
Recipe_Step_Detail_c.Catalog_Itemc FROM Recipe_Step_Detailcs) FROM Media_Prep_Order_Recipe_Steps_c
^
ERROR at Row:1:Column:1137
Didn't understand relationship 'Recipe_Step_Detail_cs' in FROM part of query call. If you are attempting to use a custom relationship, be sure to append the '_r' after the custom relationship name. Please reference your WSDL or the describe call for the appropriate names.
SQLState: 50000
ErrorCode: 30504