Constant SEAL_WAIT 

const SEAL_WAIT: Duration;

How long a read whose copy needs an unapplied seal waits for the fold before refusing.

The window cannot stand in for the fold here. A seal’s history is not ringed, so nothing the fill below can reach carries it; only the fold’s own apply does. That apply lands in milliseconds when the fold is running, so this bound is reached only by a fold that is not - and a refusal costs the client a whole re-ask (client/src/session/live.ts), so the wait is what keeps an ordinary lag from paying it.