Ghost units scattered throughout the level

Happens randomly during gameplay. It's not possible to click on, and I now belittle myself for not trying to throw a potion or cast a spell on them other than Recall, since it didn't seem to work (I recalled the whole army, and the flowers didn't move). The flower isn't simply something that lives on its own, since it seem to express the mood that changes as the time passes by, often displaying one of the bad moods, that hints the creature actually got stuck there and can't get anywhere it wants to.