Sometimes when using autofill for booking tickets, what people think they entered ends up partially wiped out before the customer clicks to purchase the ticket.

If the name was truncated down to one letter despite passport having the name having many more characters, the odds of the ticket being useful for the trip as booked plummet when it comes to international travel that involves dealing with passport control. [The issue tends to most commonly involve the airline making a fuss even when passport control commonly doesn't care.]