Quota Arrangement showing wrong Assignment in the Source

Hii Guru's

I have configured Quota arrangement, But it showing error in assigning the source, Kindly help me out with the solution

Now with the help of above created quota i created PR where when i give the qty of goods as 20 and when i click on the assign to source button the system is suggesting me other option rather than showing the last 400008 Vendor, Please can any one help me in solving the query..Suggestions are welcome