to answer your question (even if it didn't necessarily happen in THIS particular case), yes.
knock tends to have a "hysteresis." in other words, there is a dependency on past events. once knock starts it tends to keep going.
as an example, say you can run 15* of advance with no knock whatsoever. in the quest for "mo powa" you try to dial in another degree. the car knocks and the EMS by some mechanism pulls one degree, which nets 15. the car still knocks. the EMS must dial it back to 14 degrees to STOP the knock. once things are stable the EMS may or may not dial back in some advance. 15 will likely work just fine again (it did before), but if it goes to 16 then it'll be necessary to drop to 14 once again to quell it.
of course if the EMS is operating properly this all happens in the fraction of a second. nevertheless the fact remains that an operating condition that runs without knock may NOT be stable IF knock just occurred.
fwiw
ken