Resource dependency was configured so that resource A requires resource B. But when placing purchasing additional amount of resource A via CCP or PCP resource B is not added to the order.
The issue happens when limit of resource A in subscription is non-zero, e.g. resource is configured with non-zero Included value or was purchased previously. It is caused by bug PBA-50920 which is fixed in PBA-E 5.5.1.
Please upgrade to the latest version of PBA-E.