Captivate 8 multi slide video synchronization

Using Captivate 8.0 to publish short lectures.

Projects are created from existing Powerpoint slides. Insert a video across multiple slides, edit the video timing then publish to video.

The resulting mp4 video plays fine for the first slide or two but will lose synchronization when transitioning to a slide later in the lecture. This could be the 4th, 5th or later slide. Symptoms are that the video shows the loading wheel, then repeats a part of the video and loses synchronization with the audio. This pattern repeats every few seconds for about 5 or 10 attempts until the slide, the video and the audio are all out of synch with each other.

Captivate 7 had the same problem.

From memory, Captivate 7 did not have this problem if it was published to SWF. Unfortunately SWF is not a YouTube supported format.

Does anyone have a fix for this?