A computer glitch was a glitch which involved a computer.
In 2366, Lieutenant Worf noted that sensors aboard the USS Enterprise-D indicated that a Borg vessel fired energy weapons at them, but it was soon discovered that no such vessel was there. In response to Captain Jean-Luc Picard questioning whether it was another computer glitch, Lieutenant Commander Data postulated that Worf had seen a synthetically generated image. (TNG: "Evolution")