There are more options, e.g. the LHS PIC needing an instructor for reasons of recency.
Yet the Chinese official media are typically correct about what they are trying to say. F/O sounds like an F/O, especially if announced on the CAAC News website (did not check myself).
Link click here.
Some is easier to imagine, such as a long-time LH instructor having enough of surfing the timezones and coming back to 737 i.s.o. 777/787, some harder. How does 31k hours fit within one lifetime?