Masking experts please help

I have an animated mask. The mask consists a few layers.
Why is there a “white” overlap on the “right wing”?

I have enclosed a sample fla.

Thanks in advance.

I don’t know why it happened, but I’ve fixed it by changing the cross to a movie clip and adding another layer on top of it.

Thanks ignusb, I saw the fix you made on the cross adding an orange background to fill in the hole. That was very clever. But that was just a practice file to find out why it was doing that problem and would like to know how to go around it other than making a “patch”.

My sincere thanks for your help.

Anyone, please help solve this mystery?