This perhaps technically not be a bug, but this is a *usability* bug. Upon choosing in the "Styles and Formatting" a paragraph style, and pressing "More options", it is natural to assume that its changes are applied to every place with the style (including the future), excluding manually formatted. What happens instead is that the changes are only applied to the current paragraph.
Where is this "More options" located? Set to NEEDINFO. Change back to UNCONFIRMED after you have provided the information.
Sorry, I can't reproduce this anymore. But ATM I'm from another PC and distro, so it may be either that it was specific to a document, or it was fixed (though lowriter version is the same). FTR, here it's tested with "libreoffice-fresh" Archlinux package, as opposed to "libreoffice-still" one.