I thought 170 was just the peak with the average heat produced being equivalent to 120. What happens if I get bad voltage from the mains? Hopefully the fact that the LEDs are underdriven will help protect them. What if one burns out? I'll have to unplug the system and replace it.
Again, if you had read the resource I pointed you to, you would realise that a small increase in voltage can cause a large change in current, AND that you can't predict the actual current for a specific voltage.
has pointed out, LEDs should be driven from a current source, not a voltage source.
The difference between the average and the peak voltage for AC is 40%. LEDs are not operated by heating (as incandescent bulbs are) so the equivalent heating isn't particularly relevant. One of the very first things in the resource I pointed you to is the difference between incandescent bulbs and LEDs.
A 40% increase in voltage will cause an increase in current significantly greater than 40%. It might be 100% more, 400% more, or 1000% more. This might make the LED just go POP and die immediately, or it might heat it causing the next peak to draw more current, which heard it more, causing it to draw more current until it goes POOF. Or it might appear to do nothing, but you find that it's life deceases from the typical 20,000 to 40,000 hours to 5000 hours, or 1000 hours, or 100 hours.
And when it fails it might fail short circuit which will cause all the other modules to fail in an ever increasing cascade.
There fact that you see some segments light more brightly than others means that these will be more highly stressed than the others in that LED which may lead to a cascade failure in the LED module.
Driving a LED from a voltage source and asking how long it will last is a bit like removing your hands from the wheel while driving and asking how long before you crash.