This is how it is on mine. If I delete the fill (layer 2) it stays the same. If I delete the line (layer 1) it fixes it. When I restart LB it reverts back.
You are showing a sub-layer added to that Red layer, and I assume you set that as ‘Make Default’ for that layer. I would remove the sub-layer and set Red to Line, then make that the default. Please let us know how that goes.