[BUG] Collect key frames does not work

[Selur]

Okay, the key frame extraction is driving me crazy.
When I use:

ffmpeg -i E:\Test.mp4 -vf select=eq(pict_type\,PICT_TYPE_I) -vsync vfr -loglevel debug -an -sn -f null -

multiple times inside a Windows Command Prompt I always get the same output.
But when calling it through Hybrid, I get a different output nearly every call. WTF?!

I tried modifying the analysis of the data to redo the scan when a key frame with invalid timing infos was encountered, which lead to

Grabbing key frame positions from current video stream for better cut support on passthrough,...
Redoing key frame detection call since non valid time stamps were detected.
detected 69 valid and 1 invalid keyframes
Redoing key frame detection call since non valid time stamps were detected.
detected 33 valid and 2 invalid keyframes
Redoing key frame detection call since non valid time stamps were detected.
detected 34 valid and 1 invalid keyframes
Redoing key frame detection call since non valid time stamps were detected.
detected 32 valid and 4 invalid keyframes
Redoing key frame detection call since non valid time stamps were detected.
detected 29 valid and 1 invalid keyframes
-> detected 26 keyframes

So this will take some more time.