Home renaming smart bulbs: why Home cannot apply commands to new settings ?

I had 2 bulbs in a different name group which I now want to bring to another group. I renamed the group, I have moved the 2 bulbs into that group, but still Siri only apply to the bukb that was already to that group.

Basically:

Group 1 : had one bulb, now I can see on the app I successfully moved the 2 bulbs that were in - say - Group 2 In the bulb settings, Room is indeed Group 1 for all 3 bulbs now

If I order SIri to launch Group 1 lights ON, it only lit the bulb that was in that group originally but ignores the 2 other bulbs (Meross bulbs)

NOTE : those 2 ''new'' bulbs were working as long as these were in Group 2 and follow orders only if I bring them back to Group 2 !

What am I missing ?