It seems like there may simply not be anything in the Inventor API yet for this specific situation. LeaderNotes in drawings do not need to be attached to anything and can be created out in the middle of nowhere, or moved away from something they used to be attached to, without it seeming to cause any issues. These ones that are placed without being attached to anything can also contain links to information like standard iProperties in the 'attached model' without it actually being attached to anything, and it does not show there being an issue/error with the LeaderNote. It simply will not show any data where that information was supposed to be. Seems like there is only an issue if they were attached to something, then the thing they were attached to somehow becoming unavailable, without anyone actually moving or un-attaching it on purpose, which seems to trigger some sort of 'internal' flag or property and alert us to the issue in the user interface. Therefore, it is difficult (or impossible) to check if they are 'sick' from the API alone. Sometimes Inventor's user interface includes more functionality/behavior than we can simulate though the API yet at that time. There is a similar situation within 3D sketches and their coincident constraints when WorkPoints were originally involved. The constraints all seem to be between lines/curves and SketchPoints that got automatically generated, and their 'Attached' status can be either way, without causing problems, but once one of the WorkPoints gets deleted, the user interface indicates that there is a problem, which seemingly cant be found through the API, like there is a hidden property/status that we don't have access to or something. It would be helpful if there were a Property like 'HealthStatus' on these types of objects which would return something like the HealthStatusEnum type value. That would make tasks like this more logical or easier to manage on our end.
Wesley Crihfield

(Not an Autodesk Employee)