Right now the accessibility bridge translates isHeader into setHeading. This is not true according to Android team's response https://yaqs.corp.google.com/eng/q/1302440792333221888#a1n1 (internal only).

The correct way to use it is to setHeading when the semanticsnode has non-zero headingLevel