Could you please provide example links? maybe a logfile too, see
https://support.jdownloader.org/Know...d-session-logs and post the shown logID.
In case the format is not available yet, it highly depends if youtube signals that it will be there in future. Without that information there is no real way to differ between *not available* and *maybe available in future*.
So you setup to chose vp9 only and when it is missing, nothing is shown, correct?