The normal maps that come with the Farmer include an outline of the Soviet roundel in all positions. This map is used on all default liveries regardless of if they have Soviet roundels or not, and is also used by anyone attempting to create a livery using the default normal maps. This means that every livery not using the Soviet stars in their standard locations have a visible, albeit faint outline of the star in multiple locations. This outline is visible on all locations the star would normally be, i.e. tops and bottoms of both wings and both sides of the vertical stabiliser.
Looking into the MiG-19's textures folder there appears to be a "blank" T4 normalmap that does not include the star outline, but as best I can tell this isn't used in any of the liveries that ship with the module. This also only affects the stabiliser, there is no such alternative for the T5 wings file.
Attached are two images showing the issue using the right wing as an example, one of my own work with the default normal maps applied and one of the Cuban livery that ships with the module.