Sliders and Layers

Not knowing exactly what you want/need, nor what you took from Phil to use, I will offer a suggestion.

In the first place, when you go from base layer to layer, or layer to layer, and need to preserve a slider's setting, best design practice is to place the slider on the base, and allow it to show through on each layer. That allows you to design once, create once, and the only triggers you need are to show a specific layer when the slider is a specific value. In fact, I'm pretty sure if the slider is on the base, and can be clicked from any layer, all its trigger can be placed on the base. Next best practice  (generally a poor second) is to create sliders on layers, but to have them all refer to the same variable. A lot more work, but if it is needed, at least the sliders behave consistently and predictably.

To answer your question about variables being reset by "Return to initial state", if that were to happen, variables would be worthless. The purpose of variables is to carry information from one spot or time in the project to another. If anything other than you creating triggers could change them, they would not be reliable enough to use. Sliders change, not by states, but to match the value of the variable they reference. They are tied together. If you change the variable, or the slider thumb, the other changes to match it.