In the following sample file, an error occurs in \startformula\startalign ... \stopalign\stopformula.
The similar error occurs if I use \startformula\startmathcases.
Thank you for reading.
\starttext
\starttable[|c|c|w4cm|w4cm|]
\HL
\NC A \VL B \VL C \VL D \NC\SR
\HL
\NC $x$ \VL \startmatrix
\NC x' = \NC \NR
\NC y' = \NC \NR
\stopmatrix \VL \VL \NC\FR
\HL
\NC $y$ \VL \startformula\startalign
\NC x' = \NC \NR
\NC y' = \NC \NR
\stopalign\stopformula \VL \VL \NC\LR
\HL
\stoptable
mtx-context | run 1: luatex --fmt="/Users/graph/ConTeXt/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/cont-en" --jobname="test1" --lua="/Users/graph/ConTeXt/tex/texmf-cache/luatex-cache/context/5fe67e0bfe781ce0dde776fb1556f32e/formats/cont-en.lui" --no-parse-first-line --c:currentrun=1 --c:input="./test1.tex" --c:kindofrun=1 "cont-yes.mkiv"
This is LuaTeX, Version beta-0.70.2-2012052309 (TeX Live 2012)
...
...
fonts > fallback modern rm 12pt is loaded
! Missing } inserted.
system > tex > error on line 16 in file test1.tex: Missing ...
6 \starttable[|c|c|w4cm|w4cm|]
7 \HL
8 \NC A \VL B \VL C \VL D \NC\SR
9 \HL
10 \NC $x$ \VL \startmatrix
11 \NC x' = \NC \NR
12 \NC y' = \NC \NR
13 \stopmatrix \VL \VL \NC\FR
14 \HL
15 \NC $y$ \VL \startformula\startalign
16 >> \NC x' = \NC \NR
17 \NC y' = \NC \NR
18 \stopalign\stopformula \VL \VL \NC\LR
19 \HL
20 \stoptable
<inserted text>
}
<to be read again>
\halign
\math_both_eqalign_no_aligned ...fi \fi #1\halign
\ifcase \eqalignmode \or t...
<to be read again>
\NC
l.16 \NC
x' = \NC \NR
? x
mkiv lua stats > used config file