Broken video sample duration on Hauppauge HDPVR-2

> mp4dump -verbosity 3 "original.mp4"
-------------------------------------
[stts]
entry    16052 = sample_count=1, sample_duration=1198
entry    16053 = sample_count=4, sample_duration=1199
entry    16054 = sample_count=1, sample_duration=1198
entry    16055 = sample_count=4, sample_duration=1199
entry    16056 = sample_count=1, sample_duration=1198
entry    16057 = sample_count=2, sample_duration=1199
entry    16058 = sample_count=1, sample_duration=5994   # <- troken sample length
entry    16059 = sample_count=1, sample_duration=-3595  # <- tries to make up for lost time?
entry    16060 = sample_count=1, sample_duration=1198
entry    16061 = sample_count=5, sample_duration=1199
entry    16062 = sample_count=1, sample_duration=1198
entry    16063 = sample_count=4, sample_duration=1199
entry    16064 = sample_count=1, sample_duration=1198
entry    16065 = sample_count=4, sample_duration=1199

> ffmpeg -i "original.mp4" -vcodec copy -bsf:v h264_mp4toannexb -acodec copy "out.mp4"

> mp4dump --verbosity 3 "out.mp4"
---------------------------------
[stts]
entry    16052 = sample_count=1, sample_duration=1198
entry    16053 = sample_count=4, sample_duration=1199
entry    16054 = sample_count=1, sample_duration=1198
entry    16055 = sample_count=4, sample_duration=1199
entry    16056 = sample_count=1, sample_duration=1198
entry    16057 = sample_count=2, sample_duration=1199
entry    16058 = sample_count=1, sample_duration=5994  # <- still broken. how to fix this?
entry    16059 = sample_count=4, sample_duration=1     # <- effectively skip 4 samples, let the above sample stay on screen for 5 times the length (image freeze is notable during playback). at least no time travel anymore.
entry    16060 = sample_count=1, sample_duration=1196
entry    16061 = sample_count=2, sample_duration=1199
entry    16062 = sample_count=1, sample_duration=1198
entry    16063 = sample_count=4, sample_duration=1199
entry    16064 = sample_count=1, sample_duration=1198
entry    16065 = sample_count=4, sample_duration=1199