Confirmed, on mine .43407 gives "Invalid input". I was getting "Invalid input" earlier for 0.00001 and 0.00003 (the first two examples I tried), but now they seem to work.
EDIT: Manually typing in 10, the x^y button, then 0.43407 also gives "Invalid input".
EDIT: Strangely, now all inputs seem to work, even 0.00001 and even when I restart the calculator. Not sure why ...