Middle of Stored Procedure doesn't work sometimes

I have a stored procedure that makes several inserts into different tables. Everything inserts fine except for in the middle of the sproc. The Insert into tblHeatTransaction area only works about 90% of the time. There is no pattern to the missed inserts and the data is good. If I run the procedure with the exact same data it will insert fine.
I figured I would get this out to you guys and see what you think before falling back to look deeper at the C# code.
This is an ASP.NET C# project with SQL SERVER 2012
Take a look:

ALTER PROCEDURE [dbo].[CompleteBOLTransfer]
--(@Bolnum nvarchar(25), @HeatID int)
(@ShipDate datetime,@CustomerNumber int,@ShipToNumber int,@CarrierNumber int,@BillToNumber int,@Notes nvarchar(150),@SessionID nvarchar(50))

AS

	-- SET NOCOUNT ON added to prevent extra result sets from
	-- interfering with SELECT statements.
	SET NOCOUNT ON;
   -- DECLARE @BLNum as nvarchar(25)
DECLARE @Control as int
DECLARE @HeatID as int
DECLARE @CoilNumber as nvarchar(25)

DECLARE @FinishedSize as nvarchar(15)
DECLARE @Grade as nvarchar(15)
DECLARE @HeatNumber as nvarchar(20)
DECLARE @NetWeight as int
DECLARE @TareWeight as int
DECLARE @NoOfCoils as int
DECLARE @BOLNumber as int

DECLARE @SplitCoils as int
DECLARE @Description as nvarchar(50)
DECLARE @CustomerPONumber as nvarchar(20)
DECLARE @TrxType as nvarchar(1)
DECLARE @TrxDate as datetime
DECLARE @CoilsShipped as int
DECLARE @BLId as int
DECLARE @VendorName as nvarchar(25)
DECLARE @VendorPO as nvarchar(15)
DECLARE @RodSize as nvarchar(10)
DECLARE @VendorNumber as int
DECLARE @DetailID as int
DECLARE @NoOfCarriers as int

DECLARE @TransferFromCustomer AS int
DECLARE @GroupKey AS int
SET @GroupKey = 0
DECLARE @LastControl AS int
SET @LastControl = 0
DECLARE @LastHeatNumber AS nvarchar(25)
SET @LastHeatNumber = ''   
DECLARE @LastHeatID AS int
SET @LastHeatID = 0

DECLARE @TotalCarriers int = 0

DECLARE @err int,
        @value int

SELECT @err = @@error
IF @err <> 0
   PRINT '@err is ' + ltrim(str(@err)) + '.'


DECLARE @TransSave bit = 0
 

--DECLARE @DateReceived as smalldatetime
DECLARE @ID as int

-- Create the BOL Header Record

INSERT INTO tblBOLHeader
(
ShipDate,
CustomerNumber,
ShipToNumber,
CarrierNumber,
BillToNumber,
Notes
)
VALUES
(
@ShipDate,
@CustomerNumber,
@ShipToNumber,
@CarrierNumber,
@BillToNumber,
@Notes
)

SELECT @BLID =@@IDENTITY
FROM tblBOLHeader

-- Insert records from tblBOLTransfer into BOLDetail


    DECLARE DetailsCursor CURSOR FAST_FORWARD FOR
    
    SELECT a.[Control],a.HeatNumber,a.Grade,a.FinishedSize,a.NetWeight,a.NoOfCoils,a.VendorName,a.VendorPO,a.RodSize,a.VendorNumber,a.SplitCoils,a.TareWeight,a.HeatID,a.NoOfCarriers,a.CustomerPONumber,b.[Description]
    FROM tblBOLTransfer a
    JOIN tblOrderDetail b ON b.[Control] = a.[Control]
    WHERE a.SessionID = @SessionID
    ORDER BY a.[Control],a.HeatNumber,a.HeatID
  

    OPEN DetailsCursor

	 
    FETCH NEXT FROM DetailsCursor INTO @Control,@HeatNumber,@Grade,@FinishedSize,@NetWeight,@NoOfCoils,@VendorName,@VendorPO,@RodSize,@VendorNumber,@SplitCoils,@TareWeight,@HeatID,@NoOfCarriers,@CustomerPONumber,@Description
    
    --SELECT @Description = tblOrderDetail.Description --,@CustomerPONumber = tblOrderHeader.CustomerPONumber  
    -- FROM tblOrderDetail INNER JOIN tblOrderHeader ON tblOrderHeader.OrderNumber = tblOrderDetail.OrderNumber
    -- WHERE tblOrderDetail.Control = @Control
    
    

	

   

WHILE @@FETCH_STATUS = 0
BEGIN

IF (@LastControl != @Control) OR (@LastHeatNumber <> @HeatNumber) OR (@LastHeatID <> @HeatID)
  BEGIN
     SET @GroupKey = @GroupKey + 1
     SET @LastControl = @Control
     SET @LastHeatNumber = @HeatNumber
     SET @LastHeatID = @HeatID
  END
   
   
SET @TotalCarriers = @TotalCarriers + @NoOfCarriers   
    
    --PRINT 'Coil: ' +@CoilNumber
INSERT INTO tblBOLDetail
(
BOLNumber,
Control,
HeatID,
NoOfCoils,
[Description],
CustomerPONumber,
NetWeight,
TareWeight,
SplitCoils,
NoOfCarriers,
HeatNumber,
Grade,
FinishedSize,
GroupKey

)

VALUES
(
@BLID,
@Control,
@HeatID,
@NoOfCoils,
@Description,
@CustomerPONumber,
@NetWeight,
@TareWeight,
@SplitCoils,
@NoOfCarriers,
@HeatNumber,
@Grade,
@FinishedSize,
@GroupKey
)

SELECT @DetailID =@@IDENTITY
FROM tblBOLDetail

--INSERT INTO HeatTransaction -- (this is where it doesn't work sometimes)

SELECT @TransferFromCustomer = TransferFromCustomer FROM tblHeatTransaction WHERE Control = @Control AND TrxType = 'A'
SET @TransferFromCustomer = COALESCE( @TransferFromCustomer,0)
--SELECT @err = @@error
--F @err <> 0
 --  PRINT '@err is ' + ltrim(str(@err)) + '.'

 


INSERT INTO tblHeatTransaction
(
HeatID,
CustomerNumber,
TrxType,
TrxDate,
BOLNumber,
CoilsShipped,
LbsShipped,
Control,
BLId,
TransferFromCustomer,
HeatNumber,
Grade,
MachineID

)
VALUES
(
@HeatID,
@CustomerNumber,
'S',
@ShipDate,
@BLId,
@NoOfCoils,
@NetWeight,
@Control,
@DetailID,
@TransferFromCustomer,
@HeatNumber,
@Grade,
777
)

--I added the following to retry the insert if it didn't add the record....this never fired because it never wrote a "99" --transaction into the table

SET @TransSave = 0
SELECT @TransSave = COUNT(*) FROM tblHeatTransaction b  WHERE 
  b.HeatID = @HeatID AND b.BOLNumber = @BLId AND b.Control = @Control

IF @TransSave = 0
	 BEGIN
			INSERT INTO tblHeatTransaction
		(
		HeatID,
		CustomerNumber,
		TrxType,
		TrxDate,
		BOLNumber,
		CoilsShipped,
		LbsShipped,
		Control,
		BLId,
		TransferFromCustomer,
		HeatNumber,
		Grade,
		MachineID

		)
		VALUES
		(
		@HeatID,
		@CustomerNumber,
		'S',
		@ShipDate,
		@BLId,
		@NoOfCoils,
		@NetWeight,
		@Control,
		@DetailID,
		@TransferFromCustomer,
		@HeatNumber,
		@Grade,
		99
		)
	END
	


FETCH NEXT FROM DetailsCursor INTO @Control,@HeatNumber,@Grade,@FinishedSize,@NetWeight,@NoOfCoils,@VendorName,@VendorPO,@RodSize,@VendorNumber,@SplitCoils,@TareWeight,@HeatID,@NoOfCarriers,@CustomerPONumber,@Description
SELECT @err = @@error
IF @err <> 0
   PRINT '@err is ' + ltrim(str(@err)) + '.'
	

END -- OF CURSOR LOOP


--iNSERT INTO WIRE CARRIER

INSERT INTO tblWireCarriers
(
BOLNumber,
ShipToCustNumber,
CarriersShipped,
TrxDate

)
VALUES
(
@BLID,
@ShipToNumber,
@TotalCarriers,
@ShipDate

)


-- Update CoilLog

UPDATE t
SET Status = 'WIP'
FROM tblCoilID t
JOIN tblCoilLog l ON l.CoilID = t.CoilID
WHERE l.BOLNumber = @BLId
SELECT @err = @@error
IF @err <> 0
   PRINT '@err is ' + ltrim(str(@err)) + '.'


UPDATE t
SET BOLNumber = '',TranType = ''
FROM tblCoilLog t
WHERE t.BOLNumber = @BLId
SELECT @err = @@error
IF @err <> 0
   PRINT '@err is ' + ltrim(str(@err)) + '.'



UPDATE t
SET BOLNumber = @BLId,TranType = 'S'
FROM tblCoilLog t
INNER JOIN tblPickList p ON t.CoilNumber = p.CoilNumber 
WHERE t.FinishedGood = 'True' AND p.SessionID = @SessionID
SELECT @err = @@error
IF @err <> 0
   PRINT '@err is ' + ltrim(str(@err)) + '.'


-- Update CoilID





UPDATE t
SET STATUS = 'SHIPPED'
FROM tblCoilID t
INNER JOIN tblPickList p ON t.CoilNumber = CASE WHEN ( CHARINDEX('/',p.CoilNumber) > 0 ) THEN LEFT(p.CoilNumber,CHARINDEX('/',p.CoilNumber)-1) ELSE p.CoilNumber END
WHERE SessionID = @SessionID
SELECT @err = @@error
IF @err <> 0
   PRINT '@err is ' + ltrim(str(@err)) + '.'


CLOSE DetailsCursor
DEALLOCATE DetailsCursor


DELETE FROM tblPickList WHERE SessionID = @SessionID
DELETE FROM tblBOLTransfer WHERE SessionID = @SessionID

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