When we work with proxies, we mark the proxy clips with a "Proxy"-watermark, to differentiate between proxies and original footage. The problem is, we hat a final export and in one frame was the watermark "Proxy" visible. This is absolutely fatal! Does anyone know, how this could have happened?
Never seen this happen... and I use proxies extensively. but here are some things to try.
check to make sure your camera original is still "online" for that clip. You might also move the proxy for that clip from it's location on the media drive... and you might try smart rendering to see if that knocks some sense into premiere