I thought the only way a user could do this would be where they've added the details and the files to the 'new' form but haven't saved the form to create the connection from the library items to the parent form.
My client has found several files that have been orphaned (ie there is no value in the 'parent' lookup field) - but those files were definitely added and in each instance the form was saved.
I've advised the client to monitor the issue however it's unfamiliar (potentially world organisation wide) users that are putting in the initial requests, so it's very hard to understand how they are filling out the forms or get any time with them to monitor the inputs.
Is it possible that the client is closing the form before the upload/binding tasks have completed?
If so is there something I can do to delay the closing of the form until all tasks in the background have completed. Appreciate there is no way to control the closing of the window or tab but possibly introduce an additional delay on the standard Save form option?
Latest, I can see some of these child items were linked to a form as they have a populated lookup field, however when the documents have been edited, in some cases the lookup field is blanked out when the child item is saved. I can see this in the version history, the lookup field is suddenly blanked out.