Show us how you use your FontREgion. You probably use TextureOptions.DEFAULT while TextureOptions.BILINEAR will be better choice.
This is how I create font, you should do similiar:
public void loadMenuFonts(){
FontFactory.setAssetBasePath("font/");
final ITexture mainFontTexture = new BitmapTextureAtlas(activity.getTextureManager(), 256, 256, TextureOptions.BILINEAR_PREMULTIPLYALPHA);
mainFont = FontFactory.createStrokeFromAsset(activity.getFontManager(), mainFontTexture, activity.getAssets(), "mainFont.ttf", 30, true, Color.WHITE, 2, Color.rgb(22, 144, 189));
mainFont.load();
}
Notice that I use createStrokeFromAsset but you can simply use createFromAsset instead which is almost the same but the effect is font without stroke.