If I double click a thumb, go directly into the full editor, and create a filter that includes blemish correction (say red eye), the blemish removal does not show on the thumb. But if I make the same correction from the image in the queue, then the thumb updates as well. Also notice that for thumbs whose filters were not created in the queue, pressing on the mouse wheel does not give me an enlarged image.
Works fine here. I blemished the face of the old man on the right, and redeyed the face the middle old man.
Try closing Q and reopening. or reboot the machine... if that doesn't cure it.
Fred