With this code, in case of error in _compareRulesToList, we are ignoring the returned error, as we would have it in the "then" with the rejected status. This looks like a behavior change we don't want? We ignore errors for _sendBucketEntry but for _compareRulesToList, we actually call the reject function...

Promise.allSettled will return an array with the status for each promise, including the ones rejected:

Promise.allSettled([
  Promise.resolve(33),
  new Promise((resolve) => setTimeout(() => resolve(66), 0)),
  99,
  Promise.reject(new Error("an error")),
]).then((values) => console.log(values), err => console.log('catch', err));

[
    {
        "status": "fulfilled",
        "value": 33
    },
    {
        "status": "fulfilled",
        "value": 66
    },
    {
        "status": "fulfilled",
        "value": 99
    },
    {
        "status": "rejected",
        "reason": {}
    }
]

(and no "catch" log).

And if we are aligned, it also means this is something we do not test, or returning the error in the callback has no impact...

you are right (and I will update the code), but actually _compareRulesToList is not upposed to fail either : it calls _retryEntry, which ignores the errors. Errors on individual objects are retried a bit ; but eventually we just skip the object (or batch), relying on the periodic scan to eventually process these obejcts.