AAC-LC Won't show on timeline

I have some mp4 h264 video files that play just fine in Premiere Pro CC2018.

HOWEVER... other files that use the audio codec AAC-LC (Low complexity), play fine if playing through VLC, or even in Premiere Pro as a source file.  But when I drag the file to the time line, the audio just won't register.  I've been able to get around this by going through Handbrake, but would rather not have the hassle.

Does anyone have the answer?