Hi @matthew.feerick,
The ODS team would be best to comment, and I can see you have also posted a question in the ODS category.
My suspicion is that the UAT environment supported by the Organisation Data Service - FHIR API is not the same as the Integration (INT) environment to which the e-RS integrates.
The new Organisation Data Terminology - FHIR API does appear to connect to the Integration (INT) environment (see Environments and testing).
According to Choosing an ODS API the The new Organisation Data Terminology - FHIR API is intended to replace Organisation Data Service - FHIR API.
Again though I would wait for the ODS team to confirm.
Regards,
Adam.