Hi
We need a lot more details. Exactly what camera, GoPro, Sunpak? Which model. Which Premiere version (don’t say latest, that just came out yesterday) Exact version like 14.0.3 or whatever.
What do you mean you ‘brought them into Media Encoder”? Did you encode in some other format to get them to play? Which format?
Sorry about all the questions but difficult to answer without them.
Generally AVI is hardly used anymore in my experience. I’d expect it to record Cineform, H264, something newer. Most edit programs like video that easily plays back, like ProRes, Avid DnX, Cineform. H264 not so much, same with AVI. Your best bet is convert them all to the first two I mentioned. Files will be bigger but without your issues.
You can try Facebook group Adobe Premiere Pro Editors on Facebook as these issues come up all the time there.