Tieflings have only been inclined to evil alignments in 3e and 3.5e. In 2e their alignment restriction was only "can't be lawful good". 4e and 5e don't actually have racial alignment restrictions, just lore text stating the overall average trends, and the trend of Tielfings is usually that while they have no inherent inclination for evil or chaos, they often live with fear and prejudice being used against them, and this leads many into lives of crime or having to make questionable life decisions, similar to the lore trends associated with Half-Orcs.
