Cannot update test stream - 'Cannot use max continuous duration with test live streams'

[FreekVR]

I am trying to use the Livestream Update request via this PHP library to update an existing livestream. I did not set an explicit max_continuous_duration either when creating or updating.

The following code sets the max_continuous_duration even if I don't define it, and even if I do define it and set it to null

$updateLivestreamRequest = new UpdateLiveStreamRequest([
  "playback_policy" => [
      0 => "public"
  ],
  "new_asset_settings" => null,
  "use_slate_for_standard_latency" => false,
  "reconnect_window" => 10,
  "latency_mode" => "low",
  "test" => true,
  "passthrough" => "Test4-2"
]);
$stream = $this->liveStreamsApi->updateLiveStream($livestream->remote_id, $updateLivestreamRequest);

This then yields the following error when sending the request

[400] Client error: `PATCH https://api.mux.com/video/v1/live-streams/kgvb005y2nnF228vfurRO5CZif6UqHAr9qg9tP8hYiN00` resulted in a `400 Bad Request` response:
{"error":{"type":"invalid_parameters","messages":["Cannot use max continuous duration with test live streams"]}}

I tried the following workaround but this gives an error down the line.

[...]
// Workaround
if ($livestream->is_test) {
    $updateLivestreamRequest->offsetUnset('max_continuous_duration');
}
$stream = $this->liveStreamsApi->updateLiveStream($livestream->remote_id, $updateLivestreamRequest);

Yields

Undefined array key "max_continuous_duration" on a different line

[FreekVR]

The following workaround, DOES work;

        // Workaround - https://github.com/muxinc/mux-php/issues/68
        if ($livestream->is_test) {
            $updateLivestreamRequest->offsetSet('max_continuous_duration', null);
        }