Premier nest slows down timeline use and software, playback is fine

Im am using nested sequences from a master timeline to trickle down into cutdowns and different aspect ratios. When I drag the master as nest onto a cutdown to match it everything slows down. When I render the master timeline and go back into the the timeline with the nest, the render bar goes red. I've changed the preview settings to prores 422 LT and trimmed my project down as well. All timelines are running at the same audio spec as well as all the file types within them. I've reset my preferences as well as deleted the cache, everything is cached locally as well. What it causing this?