I'm no fan of Frank Luntz, but he made some observations about televised debates back in 2016 that have stuck in the back of my mind:
1. Polls taken in the immediate aftermath of a debate are meaningless.
2. Polls taken 48 hours to ten days after a debate tend to give the exact opposite results of those taken immediately after the debate.
3. Focus groups of voters watching a televised poll are far more informative than stupid polls.
You meant televised debate?