The defensive end was seen celebrating a late sack by putting his hand up to his throat and performing a slashing gesture to seemingly indicate that the win was secured.
In the fourth quarter of the NBA Cup clash between the Chicago Bulls and the Charlotte Hornets, Giddey marched over and confronted a fan sat in the second row.
The sports media personalities' relationship had become fraught in recent years following Bayless's exit from First Take to join rival program Undisputed on FS1 on a lucrative contract in 2016.