Durations getting screwed up

[SeismicGuy]

I posted this in the General Discussions but probably should be here.  

I am creating a slideshow that contains a combination of jpg images and short mp4 clips.  When looking at the Slides line I can see the durations of each item I place in the line.  My typical jpg duration is set at 7 seconds and the mp4 durations are whatever they happen to be.  But I I discovered an interesting thing happening and not sure why.  There was a jpg of 7 seconds followed by an mp4 of about 16 seconds followed by other jpgs of 7 seconds.  Not sure what I did but when I closed the program and then opened it up at a later date to resume the 16 second duration got applied to the jpg that was just before the mp4 and the mp4 duration changed to 7 seconds.  Glancing through the Slide line view I noticed this happening to several of the mp4s (i.e., the durations changed to 7 seconds) and adjacent jpgs changed to the duration that the mp4's originally had.  Not sure if I am describing this clearly but I wonder if there was something I did to cause this or some other weird glitch.  So I am having to go through and remove and replace the various mp4s and then adjust the jpg durations. I also discovered this is happening EVERY time that there was a mp4 next to a jpg.  Some how the jpg right before the mp4 took on the time of the original mp4 and the mp4 took on the time of the jpg (7 seconds).

Help!