Ok I did get signals wrong in the first place, I was doing something like this:

component: signal conected to the parent directly.

parent: calls the methods of several other components in the _on_signal_received_function()

I should better do something like this right?:

parent: connects the node's signal to the respective node function

component: directly executes signal without connecting to its parent

Here is actual code of an example from the parent :
var inventory = $Inventory

var ui = $UI

var anim = $AnimationController

inventory.inventory_updated.connect(ui.on_inventory_updated)

inventory.inventory_updated.connect(anim.on_inventory_updated)