First Frame is black with H.264

Hi !
I'm using Resolve 9.1 lite and i have a strange issue.
The first frame of every clips i converted in h.264 - mp4 with Adobe Media Encoder CS6 is Black.
I verify in Premiere Pro and After Effects, the first frame is a real picture, not black one.
This is.... so annoying, i rendered all my files to the exact frame i needed and the first one is not usuable.
Any idea ? Similar Cases ?
thanks !
I'm using Resolve 9.1 lite and i have a strange issue.
The first frame of every clips i converted in h.264 - mp4 with Adobe Media Encoder CS6 is Black.
I verify in Premiere Pro and After Effects, the first frame is a real picture, not black one.
This is.... so annoying, i rendered all my files to the exact frame i needed and the first one is not usuable.
Any idea ? Similar Cases ?
thanks !