No. Not quite.

The two posters immediately above me explain what's actually happening.

Succinctly, this is pretty standard for KA in certain rotations, and not abnormal for KUL either. On 33R the section of J behind doors 2 becomes big seats for Y class. And then the first class section, with the herringbone seats, becomes J class.

Ironically, I find the outport where I have encountered this the most (HGH) to be incredibly good at saving those seats exclusively for Diamonds, or at least at-airport release only and the KA employee in charge decides who gets them. Whereas at HKG, it is a free for all. Sometimes they're dropped into the seat map before OLCI, other times at OLCI, other times at the airport. And often it's first come first served as long as you have some kind of reasonable elite status like GO or OWS or higher. Although not always...we got a last minute sub to 77H to Shanghai recently with first class sold as J. I was on a "C" class fare and allowed to sit there. My traveling companion, also a DM was initially denied because he was on an "I" class fare. But this was CX368, which can have 50 Diamonds on a flight. Overall I find CX pretty good, but not always perfect at HKG, to allocate seats to their highest tiers. But if they drop OLCI or before, anyone can snag them with status.