Recorded Meeting - Video Conversion Garbled/Sped up

I've recorded two sessions today, each about 30-40 minutes. The recording output files are:

 - 6 1/2 minutes at normal speed, with the last ~30 minutes of the meeting sped up and compressed into the final 50 seconds of the recording file.

 - 9 1/2 minutes at normal speed, with the last ~20 minutes of the meeting sped up and compressed into the final 30 seconds of the recording file.

Is anyone having issues with corrupted video conversions?

I'm saving to my local PC, not the cloud.

When I test shorter sessions (2-5 minute test recordings), there is not an issue. 

Using iMovie to try to slow down the sped-up sections just results in jumpy video. The data aren't there to slow the track.