This article explains the chassis loading issue for node-slice-configured devices on Paragon. Here is the screenshot describe the error while checking the chassis details:

Based on findings, node slicing on Junos is currently not supported under DV/PA 1.0 across the ecosystem components, including EMS, HB, and PF. Enabling this capability would require a formal enhancement request, along with coordinated alignment and updates across all relevant components within the ecosystem.

Please note that this approach comes with certain limitations, as it is not integrated with EMS/HB/PF and does not provide end-to-end orchestration or scalability within PA 1.0.

So, either you can request FER or use Juniper Routing Director to avail this feature