I guess you're playing with the default keys on the keyboard.
So basically, some keyboards have trouble to handle 3 pressed keys or more, especially when an arrow key is involved. If you hit the down key again, it should cancel the lob mode...
To avoid all of this, you can try to use these keys on the numpad : 8, 4, 5, 6. It should help in most cases...
== Mana Games ==
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