Two screen-grabs are below. These boxes are appearing over two different clips treated with two different plugins within a 10 min video. I'm using a top of the line MAC PRO 2019 with the latest FCPX and OS and 192GB of mem and TWO AMD Radeon Pro Vega II 32 GB cards.
Timeline is 1080. These overlay boxes don't appear until I make ALL clips into a final Compound clip. Thank you in advance.