It was Seventeen's Jeonghan
I've never seen someone suck that much at filming
There were so many instances where no one could be seen
when one member was singing, he wasn't the one appearing on screen and it was focused on the guy moving to another formation next to him, seriously it was the worst case of bad filming..
It was a total mess
And in the end, when they were doing "Chuck" Jeonghan was supposed to appear, yet he never appeared
so Jeonghan started to sing under the stage, it was literally an empty stage
original post: here