So... I got the bugS!
First one was mine, I let the option "inline donor references", so the cylinder got inlined, and that scaled cylinder triggered Studio render bug that scales fake seam gap by the same amount...
As for snapping on cylinders, with current LDCad version you have to manually inline flex part (and loose LDCad editability). Loosely related to https://forums.ldraw.org/thread-23840-po...l#pid36311
Template corrected in my first post!
First one was mine, I let the option "inline donor references", so the cylinder got inlined, and that scaled cylinder triggered Studio render bug that scales fake seam gap by the same amount...
As for snapping on cylinders, with current LDCad version you have to manually inline flex part (and loose LDCad editability). Loosely related to https://forums.ldraw.org/thread-23840-po...l#pid36311
Template corrected in my first post!