3D FlipBook - Pixel gaps between pages

Hi, the FlipBook works well but we have a small display error. Usually between the pages or on the outsides there are gaps where other pages seem to blend in leaving some weird lines. I've tried several combinations of values but it seems it won't disappear. Tried on Desktop normal and fullscreen and on iPad newer generation. Sometimes they disappear but after switching pages it appears on the same page numbers. Is there a way to fix this? Screenshot of example: http://dba-bau.com/wp-content/themes/dba/data/flipbook_screen.png Live example: https://www.dba-bau.com/magazine/hessen-2022/

Thanks in advance