No "light up switch" when using Inovelli in 3-way

I read on the instructions somewhere that the dumb switch used should not have any lighting when used with the Inovelli switch. Why is that the case?

Because the Inovellis were not designed to work with lighted switches. I don’t believe an in-depth technical explanation has ever been posted.

I’m just curious about the technical explanation of a smart switch not being able to work with a lighted switch vs. two dumb switches being able to work with a lighted switch.

Not looking for a solution. Maybe this should go in the General Discussion section.

I’m just making an educated guess here, but the way the Inovellis work with ‘dumb’ switches is they sense current draw to determine if it needs to enable the Load terminal or the Traveler terminal. If the ‘dumb’ switch is lighted, then its going to cause a current draw for the light in the switch and that is going to mess with the ‘smart’ sensing on the 3-way circuit