Can Impermanent Loss Occur If One of the Tokens Is a Stablecoin Pegged to a Fiat Currency?

Yes, impermanent loss can still occur even if one token is a stablecoin, provided the other token's price diverges significantly. Impermanent loss is solely based on the change in the ratio of the two assets' prices, regardless of their absolute values.

If the non-stablecoin asset's price increases or decreases, the ratio changes, triggering arbitrage and resulting in impermanent loss relative to holding the assets separately. Furthermore, if the stablecoin temporarily loses its peg, impermanent loss is also triggered.