Imported Clips Missing Part of Video

I have several short clips from my phone that I used VLC to convert to H.264 MP4s.  I created a project, transferred the clips in and moved them to the timeline in the order I desired (no merging, splicing, etc to original or converted files).  Once transferred to the timeline I discovered that some clips were whole and others only showed 2-3 seconds of an aapproximately nine second original/converted clip.  I thought maybe it was a bad conversion, so I tried again with a slightly different name and even put it in a new project to test it.  These clips still start and end at the same truncated point in the clip.  Suggestions regarding whether this is an issue likely with the original file, the conversion, or Premiere Pro would be welcome, so I don't waste excessive time trying to resolve the issue at the wrong point.