Hello, I have a problem, and need help!

I use repeating events form google cal. And now I can not change project for my repeating events from google cal.

1. Add repeating event to google cal.
2. Sync and get task in today or tomorrow on iPad.
3. Change project for my tasks on iPad.
4. Sync.
5. My task has no project in web version. But task has a project on iPad.
6. After several minutes I see my task without a project in iPad too.

So, after sync all changes on this tasks abandoned on iPad.

Please, help!