The more I test the LTI LineItem service in Canvas, the more confused I seem to become. I have already reported in a separate post about line items I create not being visible within the Canvas Gradebook. Now I am finding that, if I create a line item without associating it with a resource link ID, as well as creating the line item, an assignment is also created (and automatically published). Although the LineItem service does not show that the line item is associated with a resource link, I have found that deleting the line item via the LineItem service also deletes the assignment. Likewise, deleting the assignment via the Canvas UI also deletes the line item. So there is clearly a linkage being maintained between the two, it is just that the LineItem service is not revealing this. My expectation with the LTI LineItem service was that, if a line item is not associated with a resource link ID, it would remain until deleted by the LTI tool or until the course is deleted. I have also found that if I use the Canvas UI to duplicate the assignment, a new line item appears in the gradebook but it is not associated with the LTI tool (not included in calls to the lineitems endpoint) and its endpoint is not passed to the LTI tool in a launch message.
Is anyone else able to replicate this behaviour and/or comment on whether it is behaving as designed, or if there is a bug here?