Does this customer has issues with wrong PDFs (from another company/contact) attached while sending emails via maintenance "create open invoice customer statement".
It sounds very similar to that.
Try to debug FormLinkDocumentFileNames().
More explanation @Paul:
When the issue occurs, should see if restarting presence or lookup helps. If so - that is the issue and should be sorted. First need to ensure that that is the issue...
Hello!
You can mark it as closed as option. If document is connected with other documents you can not delete it so you will not be able to delete PO, as you will not be able to remove Goods receipt...
