CX regional releases to BA have been extremely sparse for close to two years now. There's really no point puzzling over a particular date. They may or may not release space as the dates draw closer. I've seen HKG-BKK suddenly open up about six weeks prior to departure, then shut back down.
btw, it's not a "block," it's an issue of whether CX releases space in the first instance. "Block" would be BA blocking space that CX has otherwise made available to partners.