Sounds like your database is corrupt. Check your database, find your 2 entities, likely they have the same value in attribute submetaobjectname. As a result they share the same generic object, thus getting your decribed symptom.
To resolve this the simple way: delete them, if you can, and recreate them one by one. Likely deleting the second will throw an error, since its generic object has already been deleted.
To resolve it in a more complex way: create a new generic object, use SQL to add its id to the submetaobjectname of one of your two objects.
Hi Kishor M,
To get a clear idea about what you are explaining, share some screenshots here.