I guess it's a matter of married segment availability. QR834 from DOH to BKK has I availability but married QR180 and QR834 from OSL to BKK has no availability in business class, even in J.
I don't know what OP should do but I find it very bad that QR told him to solve this problem with the OTA as it's not the OTA fault but QR fault for having changed their flight schedules.