Biscuits Bundles is not compatible with subscription products, and this is a Shopify limitation rather than a Biscuits one.
A subscription is one of Shopify's purchase options, which work by attaching a selling plan to a product. Shopify does not allow products with a purchase option to be used inside a bundle. See Shopify's bundle eligibility and considerations, which states that bundles are not compatible with subscriptions, pre-orders, or try-before-you-buy, nor with the Shopify Subscriptions app.
So a product that has a subscription plan attached cannot be a component inside a Biscuits bundle.
These apps build subscriptions on Shopify's native selling plans, so a product with one of their subscription plans attached cannot be a bundle component:
Recharge - uses Shopify's subscription selling plans. See Recharge: Shopify Checkout Integration. Not compatible as a bundle component.
Appstle Subscriptions - creates and manages Shopify selling plans. See the Appstle Shopify App Store listing. Not compatible as a bundle component.
Loop Subscriptions - maps products to Shopify selling plans. See Loop: getting started. Not compatible as a bundle component.
Seal Subscriptions - its standard auto-charging mode creates Shopify selling plans (not compatible). See the Seal manual. Seal's optional "recurring invoice" mode does not attach a selling plan, so a product using only that mode would not be blocked from a bundle, though it is a different buying experience.
Note: How subscription apps work can change and is outside our control. Check each app's own documentation, and contact its support, to confirm whether it uses Shopify selling plans (which cannot be used inside a bundle).
Sell your subscription products separately from your bundles.
If you want to offer a bundle and a subscription of the same items, keep them as two distinct products.
Have a specific use case? Reach out with the details and the subscription app you use, and we will tell you what is possible.
See also: [Is Biscuits Bundles compatible with subscriptions?] and [Using Biscuits Bundles with pre-orders and other purchase options].
