A motor overheats (the current increases) when the load is heavy.
When the electronic thermal O/L relay works, you need to mitigate the load.
If the current is still large with no load, set Pr.0 (Torque boost) to a smaller value.
The following is consideration on thermal.

When using a single motor connected to a single inverter, setting the inverter's electronic thermal O/L relay to the rated motor current value can protect the motor from overheating.
Note that if the motor capacity is too small compared with the inverter capacity, the current detection precision becomes low and protection may not work properly.
In this case, use an external thermal for protection.

When using a single inverter to operate multiple motors, you cannot use the inverter's electronic thermal O/L relay to protect the motors.
Therefore, you need to connect an external thermal to each motor for protection.