Sql-server – Select permission denied when using linked server in a function unless inlining is off

We are encountering an unusual error in our beta environment after upgrading to SQL Server 2019. This occurs when selecting from a scalar-valued function. This error does not occur in our production environment running SQL 2014.

The statement is:

select function(1234567)

The error message is:

Msg 229, Level 14, State 5, Line 1
The SELECT permission was denied on the object 'function', database 'database', schema 'dbo'.

The function is:

CREATE FUNCTION [dbo].[function](@var1 INT)
RETURNS BIT
BEGIN
    DECLARE @var2 BIT, @var3 BIGINT, var4 INT
    SET @var2 = 0

    SELECT @var3= ISNULL(tbl2.field1,tbl3.field1) FROM tbl1 
    LEFT OUTER JOIN tbl2 WITH (NOLOCK) ON tbl2.field2 = tbl1.field2 
    LEFT OUTER JOIN tbl3 WITH (NOLOCK) ON tbl3.field2 = tbl1.field2
    WHERE tbl1.field2 = @var1

    SELECT @var4 = ISNULL(field4,1) FROM linked_server.database.dbo.tbl4 WHERE field5=Convert(VARCHAR(20),@var3)
    IF(@var4 <> 1)
    BEGIN
        SET @var1 = 1
    END

    RETURN @var1
END

GO

Successful workarounds:

• Individual users can execute the statement inside the function without error
• Modifying the function to include the clause "with inline = off"
• Adding the user executing the function to the sysadmin server role

I'm not sure if we've found a bug or if it's just a case of missing permissions (or something else entirely). We would like to avoid changing the code if possible; elevating user permissions to sysadmin is a non-starter.

We are running CU2. We have not tested on CU3.