It's an issue when they accidentally add another answer, this is the message that the devices received from the HQ socket:

INFO:root:{  
    'type':'questionSummary',
    'ts':'2018-02-24T02:05:13.833Z',
    'questionId':27217,
    'question':'Tuna fish is usually sold in supermarkets in which container?',
    'answerCounts':[  
    {  
         'answerId':83533,
         'answer':'2-liter bottle',
         'correct':False,
         'count':6384
   },
   {  
         'answerId':83534,
         'answer':'Metal can',
         'correct':True,
         'count':957679
   },
   {  
         'answerId':83535,
         'answer':'Burlap sack',
         'correct':False,
         'count':14190
   },
   {  
         'answerId':85893,
         'answer':'',
         'correct':False,
         'count':1666
   }
   ],
   'advancingPlayersCount':957679,
   'eliminatedPlayersCount':33411,
   'youGotItRight':True,
   'yourAnswerId':83534,
   'savedByExtraLife':False,
   'extraLivesRemaining':0,
   'c':5,
   'sent':'2018-02-24T02:05:14.084Z'
}

so it saw an extra answer but no text so it drew another box. This means that it is possible for them to add extra answers in the future (and make them actually correct).