When eating a piece of food while engaged in battle, the Action Bar Indicator will vanish and you are no longer able to scroll through the action bars with the arrow keys.

Platform: Windows

ISP: AT&T

Connection: DSL

Time: 8/8/2011

Frequency: Always

Character: Hotohori Ryu

World: Saronia

Steps:
1) Be engaged in battle
2) Eat some food (any type should cause the bug from what I tested)
3) The Action Bar Indicator has now vanished
4) The up and down arrow keys stop functioning in scrolling through the Action Bar sets
5) The arrow keys now cause the sub target cursor to tab around targets instead of scrolling the action bar even when locked onto a monster and no skills are in need of targeting to use

When soloing or tanking, it can be extremely risky to be locked out of your other action bar sets because food was eaten mid-battle. You are still able to use the current set of skills with 1-0 keys but no action indicator will be showing and that's all you can do until you finish the battle or disengage and start again.