EF Core and Entity Framework 6

I starting to incorporate a "class library" API for a desktop application that is using Entity Framework Core. Other code still resides on EF6 and needs to for now.

I am running into an error where it appears an EF Core error is occurring, but it is failing on code that is used with EF6.  The error is: System.Data.SqlClient.SqlException: Invalid object name 'dbo.GroupReports'.

This is NOT located in the entity model for EF Core

This IS located in the entity model for EF6

Why would it be calling the EF Core dll, but be for EF6?