We are on E10.1.400.20 and are trying to delete attachments from sales orders. We create these orders by copying closed orders (customer reordering same thing over again). We try to delete the attachment(s) in either the tree or the Attachment view. The attachment appears to be gone, but after Save and refresh or Save, exit and getting back into the order, the attachment is still there.
I just tested this. It looks like the form doesn’t recognize simply deleting an attachment as a change, so saving doesn’t actually do anything. If I delete the attachment AND make a change to the order (i temporarily added a character to the PO field), saving works properly and the attachment stays gone.