Stored Procedure fails to return all rows of data.

Question

Our HR database uses a procedure to build a list of employee IDs (ie. 1,3,14,...1210,1215) then calls a procedure to with a variable to extract details per employee. Unfortunately the list is 947 ids, however only 887 rows are returned.
As a test I split the list in two and called the procedure. If I add the data rows together I get 947, hence I know the employees are valid. Can anyone suggest why a long list of Ids should fail? Is there a limit a stored procedure can return?
The procedure (simplified down a bit) is:
ALTER PROCEDURE [dbo].[sp_Employee_CreateTable]
 @EmpIds varchar(4000)
AS
SELECT    E.empid as EmpId ,E.Surname
    FROM    Employee E
    WHERE  (E.[EmpID] IN (select * from GetAllUsersUnderManager(@EmpIds))) AND EJ.id=dbo.GetCurrentEmployeeJobRecord(EJ.empid)--EJ.dateto IS NULL
I can run the procedure as:
"exec sp_Employee_CreateTable @EmpIds=N'1,3,14.....999'" which returns (say) 700 rows  and  "exec sp_Employee_CreateTable @EmpIds=N'1001,.....1215'" which returns 247 rows. (ie. 700+247 = 947 which is correct.
But exec sp_Employee_CreateTable @EmpIds=N'1,3,14......1215' only returns 887 rows.
I have looked at the length of the data passed to the procedure (1,3,...1215) which equals 4126 chars, therefore I bumped the varchar space from 4,000 to 6,000 which is still within limits, however the number of rows returned was still 887.
Any help would be gratefully received.

Answer 1

Hi Scott. I run the script you suggested (thank you), the var EmpIds was set to a string with over 930 ids. The returned data set started with 0 but only had 888 rows. As mentioned above I refer the 930+ list as full list, and the 888 as the short list.
The difference (around 47) were the last values in the full list.
Although EmpIds was set to 6K it definately seems like it gets to around 4K chars then ignores any other values.
Re "since you pass....". Absolutely. I have modified the Employee_CreateTable with the var update to 6K/
ALTER PROCEDURE [dbo].[sp_Employee_CreateTable]
 @EmpIds varchar(6000),
 @IncludeLeavers Bit
AS
    SELECT    E.empid as EmpId ,E.Surname, E.Firstname as Forename,E.PayrollID, E.intextno as Extension, EJ.position as Position, [dbo].[GetEmployeeDepartment](E.empid) as Department, [dbo].[GetEmployeeLocation](E.empid) as Location,
E.title as Title, EJ.ReportsTo,
            CoEmail,E.[left]
    FROM    Employee E INNER JOIN EmployeeJobs EJ
    ON        E.empid = EJ.empid
    WHERE  (E.[EmpID] IN (select * from GetAllUsersUnderManager(@EmpIds))) AND EJ.id=dbo.GetCurrentEmployeeJobRecord(EJ.empid)--EJ.dateto IS NULL
            AND (E.[left]=0 or E.[left]=@IncludeLeavers)
    ORDER BY E.Surname, E.Firstname, E.empid