Group --only one switch toggles RFLink

I created two groups in groups.yaml
They show correct with the respective buttons in them. All switches are connected with RFLINK.

However when I change the switch of the group, or one of their respective switches, only one switch changes one light to on or off (in my case switch.shcemerlamp_groot.

When the buttons are not in a group they work correct.
What am i doing wrong ? It looks like RFlink cannot toggle all switches at the same time

Slaapkamer:
  entities:
    - switch.slaapkamer_schemerlamp
    - switch.slaapkamer_kastlicht
Kamer:
  entities:
    - switch.schemerlamp_bij_muur
    - switch.schemerlamp_groot
    - switch.schemerlamp_vensterbank
    - switch.schemerlampen_kast
    - switch.schakelaar_ongebruikt_d
```