Yellows leaves on Dendrobium griffithianum
 

Do these yellow leaves seem sunburnt, or is this indicative of another issue?

Potted by a south-facing window in medium bark. Watered in sink once a week. Atop humidity tray.

All the leaves look dessicated. Once a week may not be enough in large bark in a clay pot. Most Dens., especially this kind in Section Densiflora, shouldn't go dry during the growing season.

How long have you had it? Did you repot it recently, or has it already made growth since repotting?

Replying for the updates. By the way, if anyone over here wants to make real money then you can visit https://casinosanalyzer.ca/casino-bonuses/yabbycasino.com / here where you will find those sites through which you can easily make a lot of money. I am sure you won't regret your decision.