Pending Seat Acceptance for learners who only have one assignment

Summary:

We are seeing two behaviours which I am assuming shouldn't happen:

• Learner enrols onto offering but is put into Pending Seat Acceptance status. They have to accept the seat for their assignment to be activated
• Learner enrols onto offering and assignment is activated. Later on they return to the system to see there are two assignments on the same offering - one is active and the other is pending seat acceptance. See screenshot below.

We do not have any approval workflows on our courses, so there is no reason for an assignment not to be active immediately.

Any idea why this is happening? Is anyone else having the same problem?