[NTG-context] mkiv: missing \colon, \colonequals is just an equality sign

It seems that \colon is missing and \colonequals is mapped to the wrong symbol in the latest mkiv (I'm using the minimals). A minimal example: \starttext \startitemize \item $\colon$ \item $\colonequals$ \stopitemize \stoptext No colon is generated from the first command (in fact, nothing at all appears), and the $\colonequals$ produces an equality sign, not a ":=". Jesse