As somebody that works in IT, most problems like these can be attributed to human rather than computer error. That is to say, somewhere along the line somebody has screwed up your stored information. This might be you, any of your fellow passengers, any booking, check-in, ticketing agent or conceivably an immigration authority.

Having said that, BA‘s IT is known to be clunky and error-prone, which makes anything mentioned in the paragraph above much easier.

I would suggest that you and all of your fellow passengers check their information stored online. Each may have fellow travelers stored with varying information too.

The big „X“ from the US APC machines is completely normal. I get it every time and it feels like many others do too. Perhaps these machines were programmed by the same outfit in India that now looks after BA‘s IT.