Bug

From Styleguide

bug

A programming flaw that causes a piece of software to function incorrectly.

Bugs, or glitches, are supposed to be identified and fixed during beta testing, but some bugs inevitably wind up in most commercially-released games.

Example: Jaws: Unleashed was nearly impossible to play because of a series of frustrating bugs that caused the game to crash in the middle of frantic boss fights.

Wrong: problem, error, issue, syntax error.