Expected Results: Users with access should be able to upload attachments in Modern UX to child objects of Project.
Actual Results: Users receive an API-1007 error when trying to upload attachments to child project objects in the Modern UX.
This is caused by a defect DE59856 with the permissions in the Modern UX when a user only has instance level rights to the sub object.
Release : 15.9.1, 15.9.2
Component : CLARITY STUDIO
Fixed in 15.9.3.
Workaround: Assign Edit Global level Access rights to the object for the user.
See also: API errors - known causes for Clarity