Some notes change update date even if I just open to read them. This is web version. No click inside the note, just mere clicking on the note on the left side, and note being opened changes the update date and note moves to the top. I would say that that is a bug and not desired behaviour.

Might be that I reported this before in FB.

EDIT:

Acctually, it happens with ALL notes. Some notes when I am in "View all notes" but it happens with all notes when I am in a folder.