Hi Petr, yup actually that is not a bug, it's a special feature I added to the scene browser when clicking on a swatch.

When you click on a swatch, to assign the selection to it, if all the objects currently belonging to that style are all hidden or locked, then the objects being assigned will also assume that same hidden or locked state.

The idea for that is to help make Styles in the scene browser a bit more familiar and somewhat similar to the traditional layer system that some people are used to.

There still is not any hidden or locked state assigned specifically to the style all on its own, it is just a mechanism that alters the object state along with its style assignment in this particular case.

That only happens if you click on a swatch in the scene browser to assign the style, if you use the dropdown in the properties panel it won't do that extra stuff.

- Michael