19.3 Upgrade - Tomcat Can't Connect to Data Server

I'm working on upgrading a 19.2 instance to 19.3 and am having issues getting Tomcat to connect to the Data Server. It seems that Data Server is not listening on the port that Tomcat wants to connect with.

2019-08-31 13:59:09,396 [localhost-startStop-1] ERROR com.appiancorp.ads.designobjects.schema.DesignObjectSchemaManager - APNX-1-4408-001 - Failed to create DesignObjectSchema.
com.appian.data.client.AdsException: APNX-3-0300-000: Unable to process the request: org.apache.http.conn.HttpHostConnectException: Connect to localhost:5450 [localhost/127.0.0.1] failed: Connection refused (Connection refused)

Strangely, at the start of Tomcat startup, it does report that Data Server is healthy, so it seems a specific aspect of data-server is malfunctioning.

2019-08-31 13:56:09,486 [wait-for-component] INFO com.appiancorp.common.startup.WaitForStatefulComponents - Appian component Data Server is healthy

Data Server itself is up and running, which has been verified with health.sh.

I ran nmap and netstat and confirm that my 19.2 instances all listen on port 5450 but my 19.3 does not. The only thing different I notice is that in 19.2 health.sh reports a "leader" status of true, while 19.3 doesn't. This attribute is not documented for either version, so I'm not sure if it is related.

I am using default appian-toplogy.xml and everything else is working as expected (can log in to the migrated instance)

Has any one else seen this issue?