Incorrect prices displaying when used with WC Subscriptions

I’ve got a product set-up as a WooCommerce variable subscriptions product (using the Woo Subscriptions plugin).

This product has a checkbox add-on to choose if you want lifetime access for an extra fee.

One of the product variables is the option to pay in full at $300 – however if you select this option, the totals that display as part of the add-on are incorrect and are showing the totals from the other variable (pay in 3x monthly payments), regardless of whether you tick the add-on checkbox or not.

See below screenshot:

Any help with how to fix it so that the correct prices are displaying would be very much appreciated!

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