Sensor entity id name generation mystery

So I have created two MQTT sensors as follow:

- state_topic: "shellies/shellyem3_heatpump/emeter/0/power"
  unique_id: shellyem3_heatpump_phase1_power
  object_id: shellyem3_heatpump_phase1_power
  name: "Shelly 3EM HeatPump Phase 1"
  unit_of_measurement: W
  device_class: power
  state_class: measurement

- state_topic: "shellies/shellyem3_heatpump/emeter/0/energy"
  unique_id: shellyem3_heatpump_phase1_energy
  object_id: shellyem3_heatpump_phase1_energy
  name: "Shelly 3EM HeatPump Phase 1 Energy"
  unit_of_measurement: Wh
  device_class: energy
  state_class: total_increasing

Yet, what I get is:
“Shelly 3EM HeatPump Phase 1” has an entity id set at:
sensor.shelly_3em_heatpump_phase_1

and
“Shelly 3EM HeatPump Phase 1 Energy”
has:
sensor.shelly_3em_heatpump_phase_1_2

I’ve tried various combination, nothing ever makes sense.

Any ideas?
Thanks