Hi Guys,
Many thanks for the answers!
I'm running the Studio version 18.6.6, on an iMac Intel (Radeon Pro 64)
The video file is a recording from Epiphan Pearl (AVC HD), but I've also had this with a motion design from After Effect, rendered also in AVC. I just wanted to add some music in the motion design and the render bug.
This rendering issue have also been seen on on big project with footage from Sony FX3 (also AVC), lots of text animations, and a bit of color correction.
I also had this issue on my PC, Intel i9 9900K / RTX 2080 with the same projets.
I've tried to do the same in FinalCutPro, same footage, same edit, very few just a trim in/out, and no problems.
But it's difficult to say whether it comes from the video source or from DaVinci Resolve...
Many thanks for your expertirse