Product Association is the last stage of the sync process. When loading a Configurable Product, if you see the following this means that either the Product Association has not been performed yet as part of the sync, product association failed, or the Accumula Magento Extension is blocked:
If a Simple (Child) product fails to associate to the Configurable(Parent) properly, you can try to force re-association by performing a manual or bulk update in LightSpeed for any unassociated Child products. This generally ﬁxes the issue. The nightly inventory sync for Lightspeed Onsite should also ﬁx this issue automagically.