The bails were dislodged at the non-striker’s end, with the third umpire left to review footage and assess whether Warner or Hridoy should be given their marching orders.
It proved a contentious decision, with footage seemingly showing that Warner made his ground first.
Warner crashed three boundaries in the fourth over, including one that flew past Smith at first slip, as the Sixers posted 8-127 from their 20 overs.
Comilla Victorians later won the match by four wickets with Smith scoring 16 from 17 balls before being dismissed.
Smith and Warner were all smiles at the toss, which the former won.
Smith and Warner, both serving 12-month bans for their role in the Cape Town cheating scandal, are barred from internationals but also taking part in the Big Bash League.
The suspended superstars are set to be part of Australia’s World Cup and Ashes defence in England this year.
The batsmen, sorely missed by Australia in their four-Test series against India, could return as early as March in an ODI series against Pakistan.
“It’s up to the selectors whether or not they want to pick me,” Warner said shortly after landing in Dhaka.
“All I can do is score runs in this tournament and the IPL, keep putting my hand up and making sure that I am the best person I can be.”
National coach Justin Langer, Test captain Tim Paine and ODI skipper Aaron Finch have all recently indicated Smith and Warner will be welcomed back with open arms.