On version 2.0, build 11416 - if I have the cursor in a paragraph and attempt to change the heading of a different paragraph by pressing the heading icon and selecting the heading level, the entire paragraph where the cursor resides changes to a heading. In other words, the cursor has to be on the line of the heading you want to change.
I have no complaint and I’m not asking to change it, just didn’t know if it was a bug or the correct behavior.