There's never enough bugs in this game.
The game tends to not update often enough (or properly), especially when it comes to the Arrow count.
If you manage to have one arrow, you can keep using that arrow over and over and over... but that requires some luck. If you manage to kill the monster with the final arrow to end the battle (or perhaps a bit shortly after), you will more often than not still have another "arrow" to use.
This behavior seems consistant with the way the game updates the info on the screen, such as death by poison/HP leak. This seems to have been fixed in FF4A.
Topic: FF2/4 The "Near Infinite" Arrow Bug (Read 2056 times)