Why Aren't My Prompt Starters Displaying on My Teams Custom Bot?

Question

Hello,

I am working on a custom bot for Teams (a conversational bot). I would like to integrate a prompt starter. Two possible prompts ("Hello" and "Help") should be displayed before the conversation starts to facilitate initiation by clicking on one of these options.

I have followed this documentation for this purpose:
https://learn.microsoft.com/en-us/microsoftteams/platform/bots/how-to/conversations/prompt-suggestions?tabs=developer-portal%2Cdesktop%2Cdotnet#prompt-starters-1

I have zipped my app and the manifest look like this, with the prompts defined in the "commandList" section:

{
    "$schema": "https://developer.microsoft.com/en-us/json-schemas/teams/v1.19/MicrosoftTeams.schema.json",
    "manifestVersion": "1.19",
     ....
    "bots": [
        {
            "botId": "xxxxxxxx-xxx-xxx-xxx-xxxxxxxxxx",
            "scopes": [
                "personal"
            ],
            "supportsFiles": false,
            "commandLists": [
                {
                    "scopes": [
                        "personal"
                    ],
                    "commands": [
                        {
                            "title": "Hello",
                            "description": "Say hello !"
                        },
                        {
                            "title": "Help",
                            "description": "Display help"
                        }
                    ]
                }
            ]
        }
    ],
    ....
}

After uploading my app, when opening the bot, I expect to see the prompt options defined in the manifest.
Prompt starters are displayed (on the left) but are immediately replaced by the default view (right)

Why does this default view is displayed instead of my prompts?