Question ARKit interoperability question

I have a Unity/ARKit project I've worked on off-and-on for some years, and recently have run into an issue with interoperability between iPad device models. The app creates anchors in an environment, and then exports the world map data to a file on a server. Other devices running the app can then download that world map data and display the same anchors. The app runs on various iPad models. The problem I've run into is where a 2nd gen iPad Pro is used to place the anchors and export the world map data, and then a 4th gen iPad Pro downloads that world map and tries to display the anchors. The 4th gen iPad Pro seems to load the world map data successfully, however, it then never seems to be able to get a fix on it's position in the environment, and hence never is able to display the anchors.

I am wondering if anybody has run into something similar to this. Is there some kind of known incompatibility of world map data between different iPad models?