In the recent tutorial https://www.wowza.com/docs/how-to-transcode-live-streams-to-webm-for-mpeg-dash-playback you guys published a transcoder config for vp9 https://www.wowza.com/downloads/webm/transcoder/transcode-webm.xml
the problem is that you did a mistake when setting the width and height for 720p config
fit-height
640
360
It is important to fix so ppl trying to get a 720p preview can get that and not a 360 sh*t quality