Hero card buttons are represented as bullets after

问题:

I have developed a chat bot in node.js and deployed it to Microsoft Azure. I have done debugging locally using bot framework channel emulator and everything was perfect along with two buttons which I have added to a Hero Card. But after deploying the same code to Azure, those two buttons were converted to two bullets.

Code:

bot.dialog('/secondaryTrigger', [
  function (session) {
  var hCard = new builder.HeroCard(session)
          .title('Hi '+session.userData.splittedName[0]+'!')
        .text('Select Your Billability Please')
          .buttons([

              builder.CardAction.imBack(session, 'Billable', 'Billable'),
              builder.CardAction.imBack(session, 'Non-Billable', 'Non-Billable')
          ]);

          var msg = new builder.Message(session).attachments([hCard]);
          session.send(msg);
          session.beginDialog('/billability');
      }]);

References:

While debugging locally

After Deploying to Azure

I can not find the justification/reason behind it. Anybody faced the same issue?