Youtube Video Resolution Problem
For best results on any Youtube upload it is always best to follow the recommended video encoding settings.
Listed here: https://support.google.com/youtube/answer/1722171?hl=en

If you have followed those settings exactly and you are still having a problem it is a localized problem that will not affect everyone. 

Youtube videos do not play the exact same way on every computer nor every playback. 

I watched the videos and as predicted I had no problem with resolution, it was a constant 480p throughout.