Check the exact thermostat and relay-control circuit before changing components.
The OJ floor-heating thermostats covered by the linked nSpiration diagram are rated for a resistive heating load. A relay or contactor coil is an inductive control load; its compatibility must be established for the exact thermostat output and coil rating.
A GFCI trip is not proof that the relay coil is the only cause. Have a qualified electrician isolate the circuit and check the manufacturer-approved wiring, grounding, supply, load and control interface. Do not defeat ground-fault protection or repeatedly reset a recurring trip.
The previous universal “1 A inductive maximum” is not established by the linked thermostat documentation. Use a documented interface or control arrangement suited to the relay panel. A relay’s contact rating for a resistive heater is different from its coil’s electrical requirements.
Sources: nSpiration wiring diagram and UWG4 manual (GFCI and troubleshooting).