It's no mistake. What you're seeing is a lesser-know fad among Jedi - "Mood Sabers". Depending on the circumstances, the light saber of a Jedi can range in color from Red (anger) to Green (awe and wonder) to Bubblegum Pink (does this cape make me look fat?). There's even the unusual White light saber, that has been seen with individuals momentarily confused over the sudden disappearance of a foe following a mid-body attack.