Hi,

with a standalone installation updated today, I get smaller letters in
\frac if \setupformulas[align=flushleft] is applied. The test file
below generates the attached pdf.

/Mikael

\starttext
\startformula
z=\frac{x}{y}
\stopformula

\setupformulas[align=flushleft]

\startformula
z=\frac{x}{y}
\stopformula
\stoptext