As an editor you're going to be thrown a lot of random files. Sometimes they'll work just fine in your NLE of choice.
Sometimes they won't.
Particularly if they have been shot on a device that uses a variable frame rate.
Just now I had an issue in Adobe Premiere Pro with a file from a 2-person FaceTime recording where the video imported and worked but the audio was playing back at somewhere around 50% speed.
The culprit was likely the variable frame rate of the clip.
How did I know it had a variable frame rate?
A guess, based on the providence of the file, but also confirmed by right clicking on the clip in the Project panel and choosing Properties...
Variable Frame Rate Detected.