"Mitigated" means price passed through the zone, not merely touched it. It is one of several states, and they are worth keeping apart: the difference between "reached into" and "went all the way through" is fundamental.
Three states and the boundaries between them
Touched. Price entered the zone but did not cross it. The zone still exists as a level of interest, though it is no longer the same thing as an untouched one.
Mitigated. Price reached the far edge, meaning it crossed the zone entirely. From that moment its "unused" quality is spent.
Broken. A candle closed beyond the zone. Here it is not just the unused quality that goes but the zone itself as a level: price passing through and settling beyond it cancels the original observation.
The distinction between the second and third steps is the same as between a pierce and a break of a level: reaching inside versus closing beyond.
How it differs from a liquidity sweep
The two get mixed up because both sound like "price went there and came back".
A sweep applies to a level — a single price. A wick went beyond it and returned.
Mitigation applies to a zone — a range between two prices. Price crossed it from the near edge to the far one.
Their roles differ too. A sweep is an event on the chart, with a moment and a depth. Mitigation is a change of state in an object: the zone was fresh, now it is mitigated.
Why mitigated zones do not vanish immediately
Because the fact remains a fact: there was a gap here, or a move started here. Mitigation means the event finished, not that it never happened.
Some objects begin a second life in the opposite direction afterwards — a gap crossed all the way through lives on as an inversion, and a broken block can, under certain conditions, become a breaker.
A common mistake
Reading "mitigated" as "it worked", that is, as a successful forecast: the zone was there, price came to it, everything came true.
The term describes geometry only: price crossed this range. It says nothing about what was supposed to happen or what happens next. A zone mitigated on the way down without a single pause is marked exactly like one price reversed from.