Are any of your switches the orange glowing kind? Are they some sort of dimmer or smart switch?

No just toggle switches.

Often caused by the staples securing the wire being too tight. I would put an AFCI breaker on that circuit for safety.

By driving the staple too tight the insulation gets crushed or at least very squeezed. It's dielectric stenght is reduced and often low enough that the 120 volts can break down the insulation over time.

it is all in conduit, its never popped a breaker, continuity is good when i check all wires to ground

You may not find the two wires pinched together situation without a megger, but since it is thhn in conduit, that shouldn't be the problem. I would start by replacing both switches. There should be no other way to get continuity....

If it were backfeeding from the neutral through the lights, you can pull all the bulbs and check again, but I can't think of how the other end would be continuous to complete the circuit.

Here's what I have done. Removed both switches, wires exposed j-box #1 hot wire 118 volts, both travelers 18 and 22 volts. j-box #2 common 0 volts, both travelers 19 and 21 volts. (the travelers will light an LED night lite) I read your last comment so I pulled the light bulb from the socket. Now it get's cool ! ! !. j-box #1 hot wire 118 volts, travelers up 24 and 19 volts, j-box #2 travelers 24 and 19 volts the common now has 17 volts. I think it is getting ugly. wow heading out to get a ladder ! ! !

Are both switch boxes dead ends, just the three wires for the switch?

I guess what I am really wondering was answered by the conduit. The travelers probably run through the light box with the common that now has 17 volts. Where all these meet in the light box is probably the problem, but the conduit probably runs from switch - light - light - switch.

To dark to start with the ladder now. I put the switches back in with out the bulb and I get 42 volts on the unused traveler. That cuts in half when I put the bulb back in.

Voltage is constant in a parallel circuit and would "cut in half" on a series. Now to try and figure out if that tidbit helps ;D

The only way I can think of off hand to get a pseudo series circuit is if the wires are all pinched together behind the light fixture transfering some of the power. I doubt the wires are long enough to transfer that much voltage under normal circumstances.

Unless the metal of the conduit is acting like a transformer, but the ground continuity would probably need to be broken or have a high impedance path back to the panel somewhere. This sounds more likely only because it is effecting all three wires at the same time, even when totally disconnected

The j-boxes are both gang boxes with switches heading different ways. Box #1 has 2 separate lines feeding it but box #2 is dead when the breaker is off on box #1. I flag the remaining hot wire in the box so nobody would get burned.

I assume the conduit is EMT? Not PVC? Was this done because you are in Chicago, or just because someone thought it might be a good idea? If not because of local codes, does the person who did it know the differences between conduit and cable? Are there any ground wires run with the current carrying conductors and bonded at every box?

Just trying to get a sense of which way this is likely to head.

Just a read on a possibility

http://www.electrical-online.com/stray-and-induced-voltage/