if I emerge -avuDN world [ebuild U ] media-libs/libpng-1.2.12 [1.2.8-r1] USE="-doc" 0 kB and the next time [ebuild UD] media-libs/libpng-1.2.8-r1 [1.2.12] USE="-doc" 0 kB portage shouldn't behave this way.
Created attachment 90720 [details] emerge --info
*** This bug has been marked as a duplicate of 138736 ***