-- The Bills used two timeouts on defense after seeing the offensive formation, and then ran the same defensive call anyway.
Mahomes himself said, on the throw to Kelce, if they see the same formation to run a particular pattern, i.e., "Do it Kels, do it!" The Bills timeout allowed them to get into that adjustment, kick the field goal, and ultimately go to the championship game.
Time compression and chaos favors the defense and hurts the offense. Unless you have 12 guys out there or see an obvious mismatch, I posit it's almost always a mistake to use a timeout on defense in that situation, it will help the offense more than the defense 9 out of 10 times.