Inheritance of parameters

Its a bug or normal?
If in global configuration change something (curency or change another parametr like show "Add to cart button") this changes not apllied for already created objects (categorys\products) and start to be applied only for new objects...

That's normal. The default options are only applied to new menus and modules.
Existing menus and modules have their own options that you can access via the menu Display->Content menus/modules.