There's a uploaded costume in a project I'm remixing that won't erase. I've added some parts to it that I've drawn on, and those erase just fine. It isn't grouped with anything, when I went to the sprite it was already vectored, and it won't erase in the original project either. What do I do to make it erasable?

maybe make it bitmap, uploaded sprites can’t be erased in vector for some reason

The only way to fix it is to make it bitmap, and erase there.