One VTL is being added to the built-in basemaps in the Basemap Gallery widget, and the other is being added as a layer in the map. To load these VTLs we are getting a token from AGOL and registering it with the Identity Manager object for tiles.arcgis.com. This seems to have made it work more often for some reason, despite the two layers being public. No errors are reported to the browser console when this happens. Sometimes clearing the browser’s cache appears to help, but on any refresh from that point on they may fail to load, requiring another cache clear. However, that does not always solve the issue. Any ideas on the cause of this issue or way to continue troubleshooting would be appreciated.