I have VS 2017 with Oracle Developer Tools 18.3 (latest).
Steps to reproduce:
1. Add a new table with a foreign key to a existing table thats already mapped in edmx using "Update model from database" option
2, Validate model appears the error below:
Error 3013: Problem in mapping fragments starting at line 40082:Missing table mapping: Foreign key constraint '<FK_NAME>' from table Table1 (ColumnID) to table<DomainTable> (ColumnID): no mapping specified for the table Table2. DataModel.edmx 40083
Note:
Oracle Database Server 11g R2