Dimension and GL posting

Hello dears ,
I made following set up :
Theme installed : exclusive
1 Dimension : 2 categories - Material and Man-Hours
2 items : - Server HPxx assigned to dimension Material
               - Tehnician labour assigned to dimension Man-Hours

Let's suppose that I need to buy 1 server of 1000 euro . so I'm doing following steps :
-Direct GRN
-Entry purchase invoice for this receival
-Entry supplier payment for this invoice

After all 3 steps completed , the amount posted in Dimension is 2000 euro (doubled)
In Dimension inquiry I'm seeing that 1000 Euro are posted against GL acc. 1510 - Inventory
and 1000 euro more on GL acc. 1550 Goods received Clearing acc.
On the other side the Bank account is credited with only 1000 Euro (which is perfect)

I know that you're not offering accountancy support , but this drive me crazy. Why FA is doubling the values in Dimension ?

Am I doing something worng? How can I handle this ?

Thank you for your help !