The playback volume of any sound would suddenly become much softer after I do the following action: -Changing video playback resolution -Changing Subtitle settings -Go forward/backward or random seeking -Clicking something on the playback screen -Sometimes it gets softer in the subsequent video

Pausing and resume playback after a while helps to resume the playback volume to normal. Refreshing the page doesn't help but closing the browser and reopening the link does.