Why does Azure Data Flow convert varbinary(1000) to varbinary(max) and how can I prevent this? - type-conversion

Question

My source table, which is located in an Azure SQL Server Data Warehouse, has a column named Upline with the data type varbinary(1000). In the destination table, located in the same Azure SQL Server Data Warehouse, the data type and column name are the same. My issue is in the Azure Data Flow that is populating the destination table.
Instead of inserting the data into the sink table in the data flow, it is creating a new table in my data warehouse. Here is the create statement for the table that is being created with
CREATE TABLE [Common].[T_7be15bb497654f0c8eeb82459912f178]
(
[EmployeeSK] [int] NULL,
[EmployeeLastName] [nvarchar](max) NULL,
[EmployeeFirstName] [nvarchar](max) NULL,
[EmploymentStatus] [nvarchar](max) NULL,
[HireDate] [date] NULL,
[OriginalHireDate] [date] NULL,
[TerminationDate] [date] NULL,
[CurrentPosition] [nvarchar](max) NULL,
[PreviousPosition] [nvarchar](max) NULL,
[WorkAssignmentEffectiveStart] [date] NULL,
[Region] [nvarchar](max) NULL,
[District] [nvarchar](max) NULL,
[Site] [nvarchar](max) NULL,
[OnSiteDepartment] [nvarchar](max) NULL,
[DepartmentName] [nvarchar](max) NULL,
[ManagerDayForceEmployeeNumber] [nvarchar](max) NULL,
[Upline] [varbinary](max) NULL,
[Lvl] [int] NULL,
[dimStartDate] [date] NULL,
[dimEndDate] [date] NULL,
[dimIsCurrent] [int] NULL,
[dimHash] [nvarchar](max) NULL,
[r7ace46966877481a90d6f8039c6524b5] [int] NULL
)
As you can see from the picture (if you can see the picture), the table is giving the column Upline a varbinary(max) data type. Why is this happening? How can I stop it from happening? When I take this column out of the source and destination tables it works successfully. However, I need the column. The data flow has these activities: source, select, derived column, surrogate key, and sink. It is doing very simple stuff and the Upline is not being changed in the derived column.
Here is the error message from the pipeline that runs the data flow:
"Found an implicit conversion from VarBinary(Max) to VarBinary(1000) that requires ANSI truncation warning. This is not supported. Use the CONVERT function explicitly to execute this request." There is no convert function in the derived column activity so I can't do the suggestion it gives.
The max length of the data in the column is 24 (found using Select len(max(Upline))FROM [source table]).
Any help would be appreciated. Thanks.

Answer 1

I found a work around. In the create statement of the destination table I changed varbinary(1000) to be varbinary(max) and, at the end, I replaced this ending:
WITH
(
DISTRIBUTION = ROUND_ROBIN,
CLUSTERED COLUMNSTORE INDEX
)
GO
with this:
WITH
(
DISTRIBUTION = ROUND_ROBIN,
HEAP
)
GO
Now, the whole create statement looks like this:
CREATE TABLE [Common].[dimEmployee_temp]
(
[EmployeeSK] [int] IDENTITY(1,1) NOT NULL,
[DayForceEmployeeNumber] [nvarchar](255) NOT NULL,
[ConaEmployeeNumber] [char](10) NULL,
[EmployeeLastName] [nvarchar](255) NULL,
[EmployeeFirstName] [nvarchar](255) NULL,
[EmploymentStatus] [nvarchar](255) NULL,
[HireDate] [date] NULL,
[OriginalHireDate] [date] NULL,
[TerminationDate] [date] NULL,
[CurrentPosition] [nvarchar](255) NULL,
[PreviousPosition] [nvarchar](255) NULL,
[WorkAssignmentEffectiveStart] [date] NULL,
[Region] [nvarchar](255) NULL,
[District] [nvarchar](255) NULL,
[Site] [nvarchar](255) NULL,
[OnSiteDepartment] [nvarchar](255) NULL,
[DepartmentName] [nvarchar](255) NULL,
[UnionName] [nvarchar](255) NULL,
[ManagerDayForceEmployeeNumber] [nvarchar](255) NULL,
[Upline] [varbinary](max) NULL,
[Lvl] [int] NULL,
[dimStartDate] [date] NOT NULL,
[dimEndDate] [date] NULL,
[dimIsCurrent] [int] NOT NULL,
[dimHash] [nvarchar](256) NULL
)
WITH
(
DISTRIBUTION = ROUND_ROBIN,
HEAP
)
GO
This doesn't help me understand what is going on in the Azure data flow, but it does run successfully and insert into the table.