Learning Expiry Alert - Not working for assignments course = required, offering = voluntary

Summary:

Hello,

We built an alert to run based on learning record expiry date to remind learners 30, 60, 90 days before the learning record expires. (based on expiry date at course assignment level)

It works when learning assignment is assign as "required" offering level (= admin/manager select offering for learner directly, course & offering assignment assignment type = required)

but will not work if learning assignment is assign as "required" course level, and learner select/enroll their preferred offering delivery mode, although we still have an expiry date at course level (=admin/manager assign course for learner = course assignment assignment type = required, offering assignment shows voluntary)