I am sure this may have been discussed, but I could not find a thread, so here goes...
Trying to book a connection with a long haul and short haul flight with BA. For example GRU-LHR-SOF, in peak GRU-LHR is 30 000 and LHR-SOF is 10 000, booked together comes as 44500 instead of 40000.
This is probably the result of the change when you could pay part of the taxes with avios, however the cash component is exactly the sum of the taxes and nothing is paid with the additional avios.

When clicked on the i:
Charges applied to your flight

There are certain taxes, fees and carrier charges that are applied to your booking by British Airways, airport operators, governments or other authorities. Here you will find a full breakdown and explanation of the taxes, fees and carrier charges applied to your booking.

Government, authority and airport charges

Per adult

Passenger Service Charge - United Kingdom

USD 23.68

International Embarkation Tax - Brazil

USD 23.85

Total government, authority and airport charges*More information

USD 47.53

British Airways fees and carrier charges

Per adult

Total British Airways fees and carrier charges

USD 0.00

Total taxes, fees, carrier imposed charges or fuel surcharge, where applicable, per person

Per adultUSD47.53

Carrier surcharges are not to be paid on flights from Brazil, so it seems correct.
If I book separately, I get the correct prices, with the possibility to pay for the RFS cash tax for short haul with avios. Any idea how to pay the correct price when booking one connecting ticket? Is this a bug or the price increase is intended?