Timing Light Accuracy

Do inductive timing lights ever go bad and give off inaccurate flashes? I've got a vintage Craftsman chrome inductive light that I'm questioning because of how much initial timing my 340 wants. I've verified the TDC mark - it's spot on. Maybe this 340 just an anomaly because it seems to want 30* initial adv.

Without having a second timing light to check it against, I'm curious if these thing ever go bad.

View attachment 1715317628
Some lights have an arrow on the plug wire clip and if pointed the wrong way it will give erratic readings.