If vector art, you may have removed or not outputting a shape needed to have the look you are after.
Fills, in LightBurn, are defined by a set of shape boundaries, toggling the fill on and off as you cross these bounds as described in this post.
If you are willing to post the file for review, someone might be able to point you in the correct direction. My guess is one of the circles around the face is turned off or has been removed.