Weird bug were pasted drawing filled randomly

Hi, I'm new to Animate and animation in general, a weird bug is happening and I can't find a way to resolve it.
I did some sketches of a character and copy-pasted them, but when I move the pasted sketch, part of is just filled with the color I used for the outline, and when I move it elsewhere in the work-space, other parts of it is filled.
I just don't understand why it does this.
Thank you for your responses.