That's bizarre. You sure the camera isn't passing through some glass or anything of that sort? I've only ever gotten this look by zooming too far in or out, where I'm sort of crossing through the wall but not at the same time. Have you tried using other lights to see if it replicates the issue with those? Might be an issue with the environment or settings if it persists with spotlights.
Though, with that said, I'm not really a fan of Kindred Art's Ghost Lights this time around. I loved the previous packs prior to the 4.20 update, but these just aren't nearly as intuitive. I've been using
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with a fair bit more success. Just overall easier to change and control. Might be worth a look if these keep giving you issues.