This is what seems to be the same issue that seemed to have occurred before in that the selling_plan_groups array is empty in Liquid. Many merchants have reached out regarding this. I can provide specific examples if needed to a Shopify representative to not expose sensitive details in this thread.
Previous issue: https://community.shopify.com/c/shopify-functions/product-selling-plan-groups-array-liquid-is-someti...
@Liam
