Blink sequence runs at inconsistent speeds

Configuration
1

So I am trying to blink some lights on\off on a driveway sensor. Each toggle is 250ms apart, but wen the sequence runs the speeds are not consistently 250ms. Its often randomly slower. Any idea why?

alias: Driveway Enter
description: ''
trigger:
  - platform: device
    type: turned_on
    device_id: 7dac73ed4acd30c38ee77466184d963d
    entity_id: switch.multirelay_3
    domain: switch
condition: []
action:
  - type: toggle
    device_id: 22dea1b78463177971eb45c505d619cb
    entity_id: switch.island_lights
    domain: switch
  - delay:
      hours: 0
      minutes: 0
      seconds: 0
      milliseconds: 250
  - type: toggle
    device_id: 22dea1b78463177971eb45c505d619cb
    entity_id: switch.island_lights
    domain: switch
  - delay:
      hours: 0
      minutes: 0
      seconds: 0
      milliseconds: 250
  - type: toggle
    device_id: 22dea1b78463177971eb45c505d619cb
    entity_id: switch.island_lights
    domain: switch
  - delay:
      hours: 0
      minutes: 0
      seconds: 0
      milliseconds: 250
  - type: toggle
    device_id: 22dea1b78463177971eb45c505d619cb
    entity_id: switch.island_lights
    domain: switch
  - delay:
      hours: 0
      minutes: 0
      seconds: 0
      milliseconds: 250
  - type: toggle
    device_id: 22dea1b78463177971eb45c505d619cb
    entity_id: switch.island_lights
    domain: switch
  - delay:
      hours: 0
      minutes: 0
      seconds: 0
      milliseconds: 250
  - type: toggle
    device_id: 22dea1b78463177971eb45c505d619cb
    entity_id: switch.island_lights
    domain: switch
mode: single
2

Maybe the toggle takes a while to complete. Your trace should tell you.