I found that most covers as diaperseft marks on my dd.
We switched to Imse Vimse covers, and wool, thy seemed to be the only ones that did not leave marks. (that was 5 years ago so there may be more now lol)
Melanie-Mommy to my super hero daughter (1/2007)
bravely battling brain cancer Fight For Maddie
and our Bumble Bean (1/2013)