The following
\setupmathematics[autopunctuation={all,semicolon}]
%\setupmathematics[autopunctuation={all, semicolon}]
%\setupmathematics[autopunctuation={all,semicolon,colon}]

\starttext
\startformula
0,0;2,0,35,17,40,41\textdegree{} \cdot 365;15 \cdot 40 =
2,9;23,14\textdegree{}.
\stopformula
\stoptext

works as it should (no space after the “;” or the “,”).

With the second and third versions of \setupmathematics there is an
unwanted space after each punctuation mark.

Alan