I guess that one of \text{…} or \begin{cases} is cause.
my issue.md:
web page:
https://freshrimpsushi.github.io/hugo-issue/
I expected:

enviroment:
go version go1.15.6 windows/amd64
Hugo Static Site Generator v0.80.0-792EF0F4 windows/amd64 BuildDate: 2020-12-31T13:37:57Z