On the Details page for a bundle you'll see Used for auto-refund within the settings table. This setting indicates whether this specific bundle is issued during an auto-refund process.
For example, we'd expect a 1 credit auto-refund bundle to have Yes next to this setting since this is how the system issues credits during the auto-refund process to those customers who paid via Stripe. However, a 5 credit bundle for example should have No next to this setting as we wouldn't want 5 credits being issued back to a customer when cancelling their space on a single session.
You may also be interested in: