Glitching - What doe it mean when a game is glitching?

Glitching has 2 meanings. The most common is "Malfunctioning video game." See examples of how people use the terms.
Glitching is when a video game malfunctions. It commonly pertains to graphics, gameplay, audio, and other aspects of the game.

Meaning of GLITCH Words For Gamers [REFG]

Glitch - Wikipedia

How to do the latest duplication glitch in Zelda: Tears of the

The Glitched Attraction (Video Game) - TV Tropes

Top Ten In-Game Glitches and Their Potential Competitive Impacts

Unscramble GLITCHES - Unscrambled 243 words from letters in GLITCHES

My screen glitches out when opening certain games, and stays like

Glitch Entity - TV Tropes

Pokemon Scarlet & Violet: Strangest Glitches

How common are glitches like that? : r/turtlewow

Leading vs lagging indicators, Metrics and KPIs

Break the Internet: The Rising Popularity of Glitch Art

What happens when the Glitch power-up is applied in a game? – Help