RBS was to send a share dividend, but I got a cash dividend instead. Is this due to SEC restrictions?

Not that I'm complaining :-) but it was just an unexpected surprise. The NYSE share price fell precipitously when RBS announced the share dividend, but I (and I ume other American shareholders) received a substantial cash dividend. Is this due to SEC restrictions on the way the rights issue was handled, since American investors weren't eligible to buy new shares?