QC- freeze frame

Have rendered a project that is 2 hrs long via FCP X. FCPX rendered video without any issues or errors but QC department is showing freeze frames. We have double checked the footage and orig video is not corrupt. Created a new project removing rendered files. QC said they view the freeze frame through QuickTime/VLC. Anyone have issues with rendered final
projects with freeze frame? 

1, What is the frame size and codec of the exported file?
2, Find out if they are seeing the freeze frames in the exact same place all the time? Get timecode where it happens.
3, Are you seeing freeze frames when you play it back yourself on your own computer at those timecode?

If the answers to 2 & 3 are no, then it's a playback issues, nothing wrong with your file. Otherwise, you have a problem and we need to take troubleshooting to the next step.

It might also help to know the frame rate of the original media and the project frame rate. Also if any stored changes were applied. 

Project is at 24fps and footage is 23.9. We opened a new project and adjusted it to 23.97 but then they advised there was video stutter. 

Rate is 8192x4320. Recorded at 23.97 but project at 24. We created a new project with 23.97 but QC advised now there was stutter.
2. Yes, same spots but our QC third party advised they cannot provide Timecode but that it was under 1,000 freeze frame (2 hour long video).
3. When the film is rendered you don’t see the freeze frame (visually). When we playback in FCPX we can’t tell as the video has a hard time loading. 

Thank you! 

QC third party can't tell you what hour:minute:second the freeze frames occur at? Sorry, that sounds like they're plain lazy.

So this is 8K video, that is how long? I'm going to bet it is a simple playback issue. Send it out to Compressor to encode as a 1080 HD and see how it plays back. I bet then there are no problems. Would be a good test to try.