On the newest version of BandHelper for IOS all my black annotations are appearing in white. I often write with a stylus on my pdfs in BandHelper and the backing of the pdfs is also white.
On the Mac desctop version the annotations are still black.
This would happen if you turned on Settings > Appearance > Documents Are Inverted. You should leave that off since (at least in this case) your document has the normal dark text on a light background.
Thanks a lot. Problem solved!