If you seek official clarification of the rules, use the official FIRST Q&A system. Any answers given on chief delphi are not official, and hold no weight at the events.
https://frc-qa.usfirst.org/Questions.php
My interpretation of <R26> doesn't concern how or where the bumper is attached to the frame, only how it is supported/backed by it. No segment of the bumper that is longer than 8" may be more than 1/4" away from the frame.