Conditional fields & CF7: display problem

Hello,
I created a form with conditional fields.
There is the name, the email, the subject of the email and the message.
I need, depending on the subject of the email, to change the label in the text field below (“Your message”) asking for different information depending on the subject.
This works, but there is a problem with the conditional fields. I would like the form to remain static when changing the subject.
The idea would be to create conditional fields that only affect the label of the text field below.
How do I fix my problem?
Thank you

<label> Votre nom
    [text* your-name] </label>

<label> Votre email
    [email* your-email] </label>

<label> Objet
    [select* your-subject "Renseignement" "Vendre sa voiture" "Communication"] </label>

[group message1]<label> Votre message [textarea* message]</label>[/group]
[group message2]<label> Indiquer la marque, le modèle, l'année et les kilométrages du véhicule que vous souhaitez vendre [textarea* message]</label>[/group]
[group message3]<label> Indiquez blabla [textarea* message]</label>[/group]

[acceptance acceptance-557] J'accepte la politique de confidentialité. [/acceptance]

[submit "Envoyer"]

Conditional fields:
Show message1 if your-subject equals Renseignement
Show message2 if your-subject equals Vendre sa voiture
Show message3 if your-subject equals Communication

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