I was doing some performance tuning on my blog earlier today, when I noticed that WordPress was using my local copy of jQuery instead of the Google-hosted copy.
I followed your recommendation and turned debugging on, to capture this line:
Use Google Libraries: Another plugin has registered or enqued a script before the "init" action. Attempting to work around it.
Through the process of elimination, I discovered that disabling the Smart Youtube Pro eliminated the debug message. However, WordPress still used the local copy of jQuery.
I went as far as to disable all plugins in this instance of WordPress, but I was not able to get it to reference Google's copy of jQuery.
I noticed in the changelog that you're now using the transients API to cache the URLs. Do you think WP might be storing a reference to the local copy here because of issue found in the debug message?