batchedEffect() stops running after first update outside batch()

[medmunds]

The documentation for batchedEffect() says: "The effect also runs asynchronously, on the microtask queue, if any of the signals it depends on have been updated outside of a batch() call."

This works once, but after the first update outside of batch() the effect no longer runs for any additional signal updates (whether inside or outside a batch() call).

import { Signal } from "signal-polyfill"; // 0.2.2
import { batch, batchedEffect } from "signal-utils/subtle/batched-effect"; // 0.21.1

const a = new Signal.State(0);
const b = new Signal.State(0);

batchedEffect(() => {
  console.log(`a + b = ${a.get() + b.get()}`);
}); // logs a + b = 0

batch(() => {
  a.set(1);
  b.set(1);
}); // logs a + b = 2 (single, synchronous batched effect)

a.set(2); // update outside batch(), logs a + b = 3
await 0; // flush microtask queue

// Bug: after an update outside batch(), batchedEffect no longer runs
b.set(2); // should log a + b = 4; actually logs nothing

It looks like maybe the async case fails to re-enable the watcher.

Demo: https://codepen.io/mvedmunds/pen/xbOpbXV?editors=0011

Using signal-polyfill@0.2.2 and signal-utils@0.21.1