Ah.

src/main/java/org/genesys2/server/service/impl/RequestServiceImpl.java

@@ -252,7 +252,7 @@ public class RequestServiceImpl implements RequestService {
 			for (MaterialSubRequest subrequest : materialRequest.getSubRequests()) {
 				RequestBody rbs = mapper.readValue(subrequest.getBody(), RequestBody.class);
 				rbs.pid = pid;
-				subrequest.setBody(serialize(rb));
+				subrequest.setBody(serialize(rbs));
 				LOG.info("Updating subrequest: " + subrequest);
 				subRequestRepository.save(subrequest);
 			}