So I am in my Hitfilm 3 Express Project. In "Project" tab I have set 60 fps, 48000Hz Sample Rate (audio), 4x MSAA.
In Export settings, H.264 I do Timeline: Editor, Content Area, Export audio + video, Full HD resolution, 30 fps, high profile, Level 4.1, VBR, 25 Mbit Target, 30 max. bitrate. Audio Codec 320 Kbps. Now I export and then when watching the finished video the video is playing like half as fast while audio is still original speed. (video too slow, so audio not fitting to video anymore).