14.08.2017, 19:44
Problem is related to the source filter. 
For some reason LWLibavSource reports back 25fps not 29.976fps for the source.
-> disabling "Filtering->Vapoursynth->Misc->Prefer LibAvSource over FFmpegSource2" seems to fix the problem for me.
Cu Selur
Ps.: will do some additional testing over the next days, hoping to figure out why this really occurs and whether there is a way to detect such sources.
For some reason LWLibavSource reports back 25fps not 29.976fps for the source.
-> disabling "Filtering->Vapoursynth->Misc->Prefer LibAvSource over FFmpegSource2" seems to fix the problem for me.
Cu Selur
Ps.: will do some additional testing over the next days, hoping to figure out why this really occurs and whether there is a way to detect such sources.