Yes and no! The clip plays half way then freezes for about 20 seconds while sound continues, then video resumes.
I did create a bin but everytime I imported S20 created a new one. I guess I missed a setting when importing. I tried dragging bin contents using 2 different methods but neither worked. I've totally finished editing so don't really need them.
BIZARRE! I think I've sussed it but will need more time as the video is 59:59:00 long. The top track in my timeline is an effects animated Dog (channel ID) which because of the speed/time parameters is in 20:14 second clips which are multiply cut and pasted for the duration. On examination the freeze occurred at the beginning of one of these clips just 3 minutes into the project. When I checked the Dog clips either side they were 20:14, the freeze trigger clip was just 20:13. When I corrected this to 20:14 the video played as per normal with NO freezing. Now I have to find and check the rest of the video.
I have no idea how this .01 time was clipped or why it should affect playback or rendering that is for greater minds than mine. I will let you know if this does prove to be the uniform solution.