One graphic I was making had a still image of a politician with a green color correct on it. Now whenever I scrub through any graphic in any project that image randomly pops up. If I try to stop on the frame it's on it disappears. It's not always right in the center, sometimes it's off to the side or I only see a corner but it's still there. It only shows up when the graphic I'm scrubbing through is not rendered out but I've cleared my cache deleted all my old auto saves and it still shows up! Even when I'm not on the project that image is on it shows up. What do I have to do to get rid of this thing??
Make sure you also purge the disc cash.
What exact version number of AE are you using? There were a lot of caching issues with 13.5.0 and they've been progressively fixing them in the subsequent versions.