Ignore it. It's a BA IT bug. Been there for years. My bookings show a mix of 2 or 3 bags allowed. I had a CW booking which until last week showed 3 bags allowed each sector change to only 2 bags allowed after I changed one of the flights by 4 days. On Ba flights, F gets you 3 bags, CW and CE allow 2 bags, Economy gets 1 bag and Economy Basic gets zero. Gold/Emerald gets you an extra bag in all cabins (except on Eco Basic). Silver on the other hand gets you 2 bags regardless of cabin (except Basic).