QnA Maker Bot working in Teams private chats, but no answers when mentioned in team

I configured a knowledge base at qnamaker.ai, published it, and created a bot using Azure Bot Service.

In Teams, I created a new bot app and associated it with the deployed bot. The bot is allowed for private chats, group chats, and teams.

• If I'm in a private chat and "ask" it "deploy cosmosdb", it comes back with the correct answer.
• If I'm using the bot in a team, by mentioning it "@CS Bot deploy cosmosdb", it doesn't know the anwer.
• If I mention the bot in the private chat, I see the same behaviour: no answer.

But to talk to the bot it MUST be mentioned, so where's the problem here?

UPDATE:

Thanks to Hilton's answer below, I noticed that when you download the bot source code (in my case, it's a dotnet core project), the README.MD file states this issue and how to fix it:

Microsoft Teams channel group chat fix

• Goto Bot/QnABot.cs
• Add References

  using Microsoft.Bot.Connector;
  using System.Text.RegularExpressions;
  

• Modify OnTurnAsync function as:

  public override async Task OnTurnAsync(ITurnContext turnContext, CancellationToken cancellationToken = default)
      {
          // Teams group chat
          if (turnContext.Activity.ChannelId.Equals(Channels.Msteams))
          {
              turnContext.Activity.Text = turnContext.Activity.RemoveRecipientMention();
          }
  
          await base.OnTurnAsync(turnContext, cancellationToken);
  
          // Save any state changes that might have occurred during the turn.
          await ConversationState.SaveChangesAsync(turnContext, false, cancellationToken);
          await UserState.SaveChangesAsync(turnContext, false, cancellationToken);
      }