Effect output seems divided into sections

Hi! First time posting here. I'm suddenly having this issue where when I add an effect to a video, it looks like it's being applied in repeating "sections." You can see that even with this "Glimmer" effect, the light rays get cut off where each "section" ends. It's driving me crazy and I don't even know what to Google to find solutions, so I thought I'd post here on the chance that someone has come across the same thing. I've been working with Final Cut regularly for over a year and I've never encountered this before. Does anyone have any insight? Thanks!

Is this a third party effect? Which developer makes it?

The effects shown are 3 different ones from Red Giant Universe. I've used them all before with no issue! This just started happening today