REST API Query Result Caching?

I have an Item (Project) that can have multiple related Items (Participants). I want to add new Participants.

I do this by processing a CSV file that contains external keys for the Project and the Participant.

Using the REST API I find both the Project and the Participant and create the relationship. This works as expected. I see the updates in the MySQL database and they are reflected in the Omeka-S application when refreshing view of the Project Item.

However, if the next row in the CSV has the same Project but a new Participant, when I again perform a GET on the REST API I do not get the updated Project with the previously added Participant. Instead I get the Project as though the previous commit to the database has not occurred. Thus when I update the JSON and again commit, it overwrites the recently added Participant.

Is there perhaps some caching of query results that is causing this behavior? In other words, on the second GET for the Project, I am not actually retrieving from the database but from a cache of some type? If so, how do I avoid this on the REST API?

This can be ignored. I was not using the REST API directly but via a wrapper that has a relevant setting.