I watched our fabricator sort through the bracket tooling and he pulled out a thin packing strip that isn't in any of the fixture photos. He says it went in for some batches. I'm helping assemble the FR10 project handover, and the old released-angle results vary. I don't want to label the strip as either the cure or the cause without knowing what it did.
It went under one component before welding, but he couldn't identify the affected batches. We found a marked sketch of the contact face. Quality and the fixture designer are comparing it with current components before deciding whether any allowance belongs in the new design.