I have been having frustrating problem.

Have edited 25min video built with video from following cameras/settings:
Pana GH5 - 4K 60p 8bit 150mbps bitrate V-Log profile H264
Pana GH5 - VFR 1080p 180fps V-Log
Olympus OM-D EM1 mII - 4K 30p 100mbps bitrate H264
Sony Actioncam FXR3000 - 4K 30p 100Mbps bitrate XAVC-S
Sony Actioncam FXR3000 - VFR 720p 240fps

I choose project settings same as for the Pana. That is 4K. 59.94fps and 8bit colors.

Only effects that I am applying are Magix LUT filter to adjust V-Log profile video from the Pana and then I have fixed occasional shaky videos with Mercalli v4 stabilizer.

When I try to render the video in 59.94fps export it always halts at some random point. It is never the same place. Some times after 30% and I have gotten as far as 52% before this happens. The estimated time counter continues down to zero and then just keeps on counting. I observe in the preview window how Vegas suddenly looks like it is re-rendering a loop of around the last second before the rendering stops.

Everytime I have to kill the program with task manager. It looks like it is responsive but cancelling the rendering does nothing.

My computer is:
- Intel 4770K
- Nvidia 1070 8GB GPU
- 16GB 1600MHz DDR3 RAM (2G used for dynamic preview). No other programs are running.
- Source video files on a 4TB disk. Destination Render folder on a seperate 3TB disk.
- Running Windows 10 64bit.
- While editing I had Vegas create proxy for all 4K videos.
- I have upgraded Vegas Pro to the newest release (were on Update 3 when I started this)

Now here is what I have tried so far:
- I have tried this with disabled resampling for all video files. (since I am working witth different framerates)
- I have tried some "youtube fixes" like reloading the project as a single project file into a new timeline and render it as that.
- I have tried to render as HEVC/AVC 4K
- I have tried rendering as Mainconcept and NV encoder in 4K H264/AVC (mp4)
- I have tried to render as XAVC-S 4K
- I have tried to render this in 1080p Export.
- I have set Vegas to default settings (ctrl-shift while opening program)
- I have tried with both so4compound enabled and disabled.

Nothing works. IT ALWAYS HALTS at some random point... and that point is ALWAYS VIDEO FROM THE GH5. When I am rendering to 60fps.

What works though is the following:
- If I render the video in parts. I managed to render to 60fps HEVC/AVC in 5 parts (indicating that video source file is not at fault)
- If I render the whole timeline to a 30fps video file it completes normally. No problems at all.

Has anyone experienced something similar or has any idea for something that I can test?

This is my first take on editing videos from the GH5 and have many TB of them "waiting" for further editing. Really need this to work to be able to continue using Vegas or "risking" upgrading to version 16.