I saw a previous post a few months back about this issue. I have a7s footage and I am placing markers on the footage for reference. Premiere displays an error at the bottom right corner that says the clip can not be updated because it is busy. Markers will work on separate audio files and Canon 6D footage.
I have the latest update to Premiere 2015. Seems to be an issue with this codec. Any one found a way around this?