"Service not found" but only with concurrency

export const Foo = (bar: Bar) =>
  Effect.gen(function* (_) {
    const baz = yield* _(Baz)
    // ...do more stuff
  })

// ✅ This works 
Effect.runPromise(
  Effect.gen(function* (_) {
    yield* _(
      Effect.forEach(bars, Foo),
    )
  })
)

// ❌ This throws with `Service not found: app/Baz`
Effect.runPromise(
  Effect.gen(function* (_) {
    yield* _(
      Effect.forEach(bars, Foo, { concurrency: 'unbounded' ),
    )
  })
)