Take that contact back to the designer with the actual accepted sample range. An end block that wasn't meant to locate can still do a very effective job of holding a part off the base. More clamp could hide it.
Loader and cover both demonstrated it. Same seating result after repeated placement. Thanks, Maya, asking where it touched found the unintended locator.
Keep the revised guide identity on the nest record. The old one may still look like a perfectly serviceable spare. This settles the bench-seating fault; the planned robot-loading trial has its own checks.