Wrong Order Number(AUFNR) determination

Hello when i create a SC and i insert the Asset number and Asset-sub_number the system retreive the incorrect Order number.

I Have:

one asset 2044882 with 2 sub-asset:

Asset Sub Order Numebr (AUFNR)

2044882/001 test

2044882/002

When i create the SC with 2044882/002 the system put "test" on the AUFNR field instead of blank information

someone can help me?

Thanks to all

Tommaso