Random hold frames being added to clips when rendering or exporting

[bennzz]

My sequence is playing back fine, unrendered, but when I  "Render In to Out" or export it, some of the clips are frozen as if I've added hold frames. It's not all the clips, appears to be totally random. I've done a quick screen record to show the issue.

Any ideas? Please help!

[Warren Heaton]

Do you know the bit rate of your source footage?  Hopefully, it's 21 megabits per second or higher, but not lower than 12 to 14.

[bennzz]

I'm not sure, but it's DJI drone footage and haven't ever had a problem before. 

[Phillip Harvey]

This is more and more common to see with the HEVC coming from DJI. You can try encoding to something like ProRes 422 rather than H264, but you may actually end up needing to transcode before even working with it. DJI has always had notoriously problematic compression to work with, in my experience, and the newer 4k HEVC versions have clearly only become even more challenging.