The latest beta — ConTeXt  ver: 2017.02.19  with LuaTeX, Version 1.0.3 — chokes
on entries such as
\cite[author1, author2, and author3 2017]
and reports an error: e.g.,


lua error       > lua error on line 81 in file c_Brill09-02_Evans.tex:


C stack overflow

stack traceback:

[C]: in function 'type'

...eXt/tex/texmf-context/tex/context/base/mkiv/lpdf-ini.lua:373: in
function <...eXt/tex/texmf-context/tex/context/base/mkiv/lpdf-ini.lua:367>

[C]: in function 'tostring'

...eXt/tex/texmf-context/tex/context/base/mkiv/lpdf-ini.lua:342: in
function <...eXt/tex/texmf-context/tex/context/base/mkiv/lpdf-ini.lua:317>

If I try something like
\cite[A B and C] all is well.
Adding the commas as in \cite[A, B, and C] gets the error.
Sadly, I need the commas.

Alan