Symbol appears different inside than outside

I'm just starting out in animate and decided to put together a simple animation of an Easter chick flapping its wings. It worked fine until I clicked out of the symbol onto the parent timeline and then all fills disapeared and it became a solid outline.

I have tried:

• Breaking apart the symbol
• Removing all the frames and re-adding them
• Removing the fills within the symbol

I am completely stumped and everything I search for is swamped with other things to do with symbols, so I apologise if this is a replica post.

The video below shows the problem.

Can anyone help, thanks.

Thanks