[NTG-context] \Umathquad\displaystyle not set

Dear ConTeXt users, I have a custom slide template that I borrowed from another source years ago. It works well on my Debian machine, but when I try to build the PDF on a docker vm on Gitlab, I run into the \Umathquad\displaystyle not set error. Surprisingly, that error doesn't crop up on my machine. Here is the complete (working) repository: https://gitlab.com/kumanna/context-slides/tree/master Here is the commit that causes the error online. Notice that I am adding the {\bf \nabla} character: https://gitlab.com/kumanna/context-slides/commit/b723c15dff6d7312605947f8bf4... Here is the failed build log: https://gitlab.com/kumanna/context-slides/builds/9972477 Is there something I am missing? Thanks. Kumar