Duplicated Symbol animations going out of synced

Hi all,

I'm running into a problem with my symbols, they seem to be going out of sync in my animation. I'm using multiple instances of the same symbol.

See below link for the .html file for example of what I mean. The wings go out of sync after awhile, even though they're the same symbol.

Would appreciate if someone can help me understand what's going wrong.

https://www.dropbox.com/sh/r5tkadrj8mxb92y/dZnWA9lkEN

Thanks

wYn