Conjecture on A_f stratifications for polar representations

Let $G\,|\,V$ be a polar representation, let $f:V\to Q$ be the quotient map, and set

$$E=f^{-1}(0).$$

An $A_f$ stratification is the stratification condition described in Section 2.2.1. The A_f stratification conjecture. There exists an $A_f$ stratification of $E$.

This conjecture would make the sheaf construction used in the paper well defined for every polar representation, eliminating the need to restrict to representations of rank one or to visible representations. The source does not provide evidence of a resolution.