Uploading score from Musescore 4 to Musescore.com and then sending to YouTubre

Previously to 4.0, this process went smoothly uploading a "continuous view" score up to Musescore.com then using the button there to send to YouTube. On YouTube is looked good and the sound was great.

Now (v4), this process yields what I think is a Page View score being uploaded and the sound is terrible.

What has changed that I cannot see? or is this a bug?