This is the setup and the settings that I use. So revert all changes in Kodi back to default and try to apply the same for testing.
Kodi settings -> Player:
Videos: Playback mode 3D = Preferred mode
Language: 3D depth = 5, size = 24, style = normal
Kodi settings -> Interface:
Skin: 3D = 5
Kodi settings -> System:
Display: Resolution = 1080p 60fps, 3D preferred = Same as movie
A screenshot of how it looks for you might be helpful to give further advices. The issue might simply be related to the subtitle style if you have not changed from “bold” to “normal”.
Then look into your TV settings and make sure that all display processing aspects are turned off (the names might be different for LG compared to Samsung)
Picture mode is set to Cinema
Dynamic Contrast Off
Clean Digital View Off
Auto Motion Plus Off
Make sure your TV actually show the correct 3D mode by pressing the 3D key on your TV’s remote and look into if there are any 3D settings for your TV