I ended up getting things working again by deleting the Custom Namespace entry. In order to do this, I had to first delete all UDT tags references, along with the namespace root folder that the MQTT Engine creates. This time while configuring the new namespace, I have narrowed the scope of the subscription to “application/26cff63b-1b2c-429b-8210-fc3985035143/device/+/event/up” which should only return the uplink payload data. With the previous scope “application/26cff63b-1b2c-429b-8210-fc3985035143/#” it would return every piece of MQTT data in the application, including downlink data, which likely resulted in different or overwritten tags when a device goes out of range and then reconnects.
This post helped provide some insight: MQTT Publish Error - #7 by wes0johnson