Really?

Any FTer worth their salt would have checked the Avios calculator, which remained correct. Any FTer worth their salt who had a forthcoming WT+ booking would have checked their MMB information, which remained correct. Both of those would have pointed strongly to there being no change.

So given the possbilities that this was either an unannounced marginal earning change introduced by stealth, or alternatively a small typo in a new page on ba.com, which was the more likely?

It really takes a special kind of overheated obssessive to demand that this be changed over a weekend. Why isn't Monday good enough?