Madrid Flights (31 Aug) - IT Glitch?

On the 31 August there appear to be ZERO BA/IB bookable flights on the LHR-MAD route, but plenty of availability on dates either side. Is this some technical glitch or are they really all full?? If so I find that quite odd.

I don’t have a Expert Flyer subscription but looking at the free seat maps available they appear to be operating, of course the empty seats could fill up with those who haven’t selected but still seems strange. They were all showing yesterday or the day before?

Anyone have any ideas?

Thanks