In What Scenario Is Impermanent Loss Actually Realized as a Permanent Loss for the Liquidity Provider?
Impermanent loss becomes a permanent loss for the liquidity provider (LP) upon withdrawal of the liquidity. If the LP withdraws their assets when the price ratio has not returned to the initial deposit ratio, the loss is realized.
Furthermore, the loss is permanent if the accrued trading fees earned by the LP are less than the impermanent loss incurred. If the fees outweigh the impermanent loss, the LP still profits overall, but the "loss" component relative to holding is still realized.