Problem with light groups and Alexa voice control

I’ve created groups for 4 bedrooms. Each group controls the bedside lights. Groups are bedside, bedside 1, bedside 2 and bedside 3. I can use Alexa to turn them all on or off. If I try to dim the bulbs, it only works on the bedside group, not the bedside 1, bedside 2 or bedside 3. If I try one of the others, Alexa says “That value is out of range for device bedside.” I can control the dimming for all of them using the HA app. I’m not sure why Alex has problems with bedside 1, bedside 2 and bedside 3.

Here’s config for my groups:

light:

  • platform: group
    name: Bedside
    entities:
    • light.mb2
    • light.mb3
      name: Bedside 1
      entities:
    • light.bed1_1
  • platform: group
    name: Bedside 2
    entities:
    • light.bed2_1
  • platform: group
    name: Bedside 3
    entities:
    • light.bed3_1