• Symbol.remove(); ->   Move the "broken" symbol on most-top-layer, why?

Like I said in your other thread:

Do you have screenshots before and after?

Show us your code and an example file please.

I never heard about such problems.

Try the following code. The symbol instance stays on the original layer.

var aDoc = app.activeDocument;
var sym = aDoc.symbols["Band"]; // symbol "Band" should alredy exists in your document
var aSymInstance = aDoc.symbolItems.add(sym);
aDoc.layers.add();
aDoc.layers.add();
aDoc.layers.add();
aSymInstance.breakLink();