SQL Database Primary Key disappears from couple tables

SQL Database Primary Key disappears from couple tables. I don't know the core reason why this happened I'm still investigating it. In mean time maybe someone had similar problem, because nobody did remove them. So far I think it’s kind of related LINQ to Entity model it could happen but I’m not sure why.

I got the error below as the matter of fact it was working properly before

Unable to update the EntitySet 'TableName' because it has a DefiningQuery and no element exists in the element to support开发者_运维知识库 the current operation

Any suggestion will be appreciated. Thanks

SQL Server replication does not produce primary keys when creating tables. If there's a replication job that recreates these tables, that'd be the problem.