Projected APY
How you're paid. Each epoch's yield is paid out over the following week. The Senior and Junior amounts are fixed at the report and shared by whoever holds each tranche while it pays out, so new deposits lower that tranche's rate.
What the app shows. A trailing 7-day APY: what the last week paid out, so it lags behind.
What we show. The latest reported payout, spread over today's balances, so you see its rate before the app catches up. The amount is fixed at the report, but the rate moves as people join or leave each tranche. It's not a guarantee of future payouts.
Unstaked mzUSD earns nothing itself, but it is deployed in the strategy and all of its yield goes to Senior and Junior. That multiplies the rate for everything staked. Every rate is APY, because yield compounds in the vault.