Inconsistent or no audio on timeline from MTS files

[sduffy1986]

I've had this problem for months and it's costing me so much time and energy. Before this issue started, I would use the Media Browser to navigate to the MTS files, and either drag and drop to the timeline or import them. Either way, worked fine. 

If I were to do this now with, say, two files, one file will show no wave form in the timeline. The best part is that doesn't even mean anything, the file might play audio fine, and the other one that shows a wave form won't play at all. Sometimes when I export a timeline that is playing fine the final MP4 won't play, or vice versa. It's so random it would be funny if it wasn't so infuriating. Any help is greatly appreciated.

(And to anticipate this question, yes my files are fine, they all have audio when I play them natively)