Can you cite this? It's not YAML execution syntax, surely Github doesn't do it, the only vector I can see is if you put it unquoted into a shell script inside of a GHA yaml.
All you need is user content containing `backticked`, and a github action referencing that via eg "github.event.issue.title" where the shell would normally execute `backticked` as a command (like echo, cat, etc).
edited: not "will", may depending on your GHA