Wrong output title in SOST from PO

Hi,

when I release massively (ME28) POs and messages ZNEU (fax output) are all generated in the same moment, sometimes in SOST I see the same document title for more than one PO (for example I see doc. title: PO 8000001263 not only for PO 8000001263, but also for 8000001262).

NACE:

Do you know if is there any note?

Thanks