Prores 4444 Export Bug in 12.5.1?

I have discovered a possible bug with exporting 4K prores 4444 on Resolve 12.5 that I hope the blackmagic team can look into.

We have a beefed up iMac 5K and do quite a bit of 4K work on it in Resolve. It's dropping frames in exporting prores 4444, but is fine with prores 422 HQ and DPX 10-Bit at 4K. We restored the iMac back to factory to make sure, but the problem still existed. Could this be a bug with software in Resolve?

Thanks.

iMac Retina 5K, 27 inch
4GHz Intel Core i7
32 GB 1600 MHz DDR3
AMD Radeon R9 M295X 4096 MB

What do you mean by dropping frames on export? The exported file is missing frames?

We get a Resolve error message that reads "640 frames dropped" then the export no longer continues.

Usually, this means your GPU is being maxed out, but in this case, we have plenty of GPU. It's fine with even heavier exports such as DPX. Just the prores 4444 is having the issue.

Wow, that's strange. 4GB of RAM in GPU is not a lot for 4K work, perhaps ProRes4444 takes it over the limit for certain shots. AFAIK the CPU is supposed to handle the ProRes part of the export, but maybe the GPU is playing a tiny role too.

I do the bulk of my work on bigger systems, but this iMac comes in handy for overflow work.

I'm using the same iMac 5k and have issues with 4k output when using temporal noise reduction set to more that 1 frame. It is likely that the GPU memory is not enough for Resolve.

I have also had the same problem.