They did announce a time delay, but it may have been 2 minutes instead of 5.
The only reason I can think of for a time delay is so that technical geniuses can substitute something for Biden missteps. Perhaps not change his words, but eliminate his staring into space dementia type pauses The debate will be simulcast on many outlets so the total time has to be the same. I do not trust CNN at all.
This debate should be broadcast live exactly like C-SPAN does congressional hearings.