It does look like mite damage that led to a secondary infection too. If you rub a tissue on the bottom of the leaf and it shows red streaks, you will know for sure. I would immediately remove this and any other affected orchids away from the healthy ones. Then follow the advice in the other thread about how to get rid of these pests. Also, I would recommend doing the tissue test on whichever orchids were closest to the infected ones, even if they don't look bad. Better safe than sorry.