1. I'm not sure exactly what you're referring to where the color changes, but the issue I did see was at around 2 seconds where a lot of the text is missing. If this is what you're referring to then you can send us the XOD document and we can take a look into why that is happening. If this isn't the issue you're referring to then can you clarify what you mean exactly and at what time in the video does it occur?
2. For this issue my guess is that when you're scrolling quickly and close together that sometimes the two quick touches will register as a double tap and zoom you out. You could either disable double tapping by removing the double tap handler (see MobileReaderControl.js bindEvents) or you could modify jquery.doubletap.js and change DIST_THRESHOLD to something smaller.
PDFTron Systems Inc.