FBL3N - Reference Key 1 (xref1) is missing

Hi,

I've some technical difficulty here. I've posted a transaction using F50 (with the stand posting keys and document types), I've enabled the referece key 1 and reference key 2 with values and successfully saved the document. It seems that when I use FBL3N and look display the 2 columns, it does not show any values.

However, when I look through the BSEG table, xref1 field using se16, the value is there and even drill down from the document it's also there. I just cannot see the value in the fbl3n column. The version which I'm working on is ECC5.0 I was wondering any of you have experience this? Thanks.