Excellent point. They do mention performing an experiment with large angular displacement and a larger vacuum. > To definitively rule out any residual concerns

Excellent point. They do mention performing an experiment with large angular displacement and a larger vacuum. > To definitively rule out any residual concerns about thermal error sources, future test campaigns could employ a test apparatus capable of measuring small torques over much larger angular displacements. For example, a Cavendish balance approach properly designed to allow very large rotation angles such as 90, 180, or even 360 deg will not be susceptible to this type of thermal false positive.