When the iATS scheduler runs a recurring profile which is linked to a membership, the contribution is not being linked to the membership, and thus the membership end date does not increment. Ideas?

Drupal / CiviCRM 5.x / iATS ext 1.6.2

Update; 8/30 looking for ideas here: https://github.com/iATSPayments/com.iatspayments.civicrm/issues/217

In this issue KarinG states: " iATS extension itself just takes care of the monies; we use repeattransaction API in 4.7 -> and the fact that the recurring series is attached to a Membership - that should update it."

I think it might be due to an extension or configuration - will report back. Will check the logs.