Moving Standard Button to Custom: Button-Card issue

Attempting to have a button that sets operation mode of my water heater to “High Demand” for an hour and then back to “Heat Pump”. Using a normal button, is there any reason why this code works perfectly as intended:

show_name: true
show_icon: true
type: button
tap_action:
  action: toggle
entity: input_button.hot_water_boost
hold_action:
  action: call-service
  service: water_heater.set_operation_mode
  data:
    operation_mode: heat_pump
  target:
    entity_id: water_heater.heat_pump_water_heater

But this code does not?

type: custom:button-card
show_name: true
show_icon: true
tap_action:
  action: toggle
entity: input_button.hot_water_boost
hold_action:
  action: call-service
  service: water_heater.set_operation_mode
  data:
    operation_mode: heat_pump
  target:
    entity_id: water_heater.heat_pump_water_heater

My final goal is to get the icon color to change based on the operation mode of the water heater, but for now I just want to get base functionality working. I keep getting the error “failed to call service input_button.turn_off. Service not found” on tap and “Failed to call service water_heater/set_operation_mode. required key not provided @ data[‘operation_mode’]” on long press. I added the long press option in case I wish to manually go back to “Heat Pump” operation before the 60mins is up.

Automation script using the input_button.hot_water_boost helper is below:

alias: "Utilities: Hot Water Boost"
description: ""
trigger:
  - platform: state
    entity_id:
      - input_button.hot_water_boost
condition: []
action:
  - service: water_heater.set_operation_mode
    data:
      operation_mode: high_demand
    target:
      entity_id: water_heater.heat_pump_water_heater
  - service: notify.mobile_app_amos_iphone
    data:
      message: Boost Mode Activated for 1hr
      title: Water Heater
  - delay:
      hours: 1
      minutes: 0
      seconds: 0
      milliseconds: 0
  - service: water_heater.set_operation_mode
    data:
      operation_mode: heat_pump
    target:
      entity_id: water_heater.heat_pump_water_heater
mode: single