There was a C3 issue that caused problem with project files, the latest release was a workaround that solved _some_ of the problems (but obviously in your case caused more.) I made the last version before this change available again.
In the latest C3 beta version, a new SDK API was added to fix the C3 issue and I will release another version (which requires the use of the latest beta later tonight.)
Thanks for the detailed error report, it is appreciated to help me through the process of debug.