The hippocampus doesn't just focus on associative relations but also premises memory on reward signals. This implies that a "learning" terminal reward is some kind of signal to the hippocampus, and I would imagine it's to mark where in-context learning happened. pubmed.ncbi.nlm.nih.gov/21851992/

A neoHebbian framework for episodic memory; role of dopamine-dependent late LTP - PubMed

According to the Hebb rule, the change in the strength of a synapse depends only on the local interaction of presynaptic and postsynaptic events. Studies at many types of synapses indicate that the ea...