It looks like the discount is no longer being offered on "any published retail World Traveller (economy), World Traveller Plus (Premium economy), Club World (business class) or First fares on ba.com via exclusive link". A sneaky introduction of rule 15 "Other significant restrictions may apply."?

There are a number of days where the little red text "Discounted" is not shown on many of the fares. E.g. for the outbound flights on Nov 16 a discount is offered in WT and First, but nothing in Club. Picking random flights on Nov 16 outbound and returning Nov 25, both listed as "Discounted", also only yields a discount of $65 instead of the expected $130 for a WTP ticket. Indeed, it's all a bit odd.