REST "identifiersouce" endpoint fails for IdentifierPool sources

Seeing this on humci.pih-emr.org, using idgen 4.7.0.

GET https://humci.pih-emr.org/mirebalais/ws/rest/v1/idgen/identifiersource?v=full&identifierType=a541af1e-105c-40bf-b345-ba1fd6a59b85

yields error 400:

[converting class org.openmrs.module.idgen.IdentifierPool to org.openmrs.module.webservices.rest.web.representation.FullRepresentation@69b5e0cc]

at org.openmrs.module.webservices.rest.web.ConversionUtil:408

Detail: see paste