Users being unsubscribed from LearnDash courses when they purchase a memberhip

I’m having an issue where when a customer signs up for a membership, they are automatically unenrolled from all previously purchased one-time payment LearnDash courses.

Use case: we have a couple of flagship, accredited courses which are sold for a one-time payment through LearnDash’s WooCommerce integration (not through PMPro). Separately, we also have a set of additional courses which are sold via a monthly membership with PMPro (two options: basic or ultimate subscription). Most users start by buying our flagship course, then buy the membership as an add-on later on (it’s one of our upsells).