Hi!

In the newest version (ConTeXt  ver: 2016.08.08 21:28 MKIV beta  fmt:
2016.8.9  int: english/english) the document

\starttext
$(1+1)$ and $\bigl(1+1\bigr)$ and $\Bigl(1+1\Bigr)$.
\stoptext

compiles to the attached file. For \big and \Big the ( is ) and the )
is (. I think this is a bug. I have not tried other sizes.

Best regards, Mikael