Using the latest release (ConTeXt  ver: 2024.06.16 18:22 LMTX  fmt: 2024.6.17, the following renders correctly with  pagella but not cambria.


\setupbodyfont[cambria, 12pt]

\starttext

\startformula
s\of(1) = s\of (\set{0}) = \set{0} \cup \set{\set{0}}
\stopformula

\stoptext


__martin