☒ There isn't really a rule, but more practices that I've come about. Basically, and whenever possible, instance variables shouldn't go in a partial. It's too easy to reuse the partial and forget to declare the instance variable. Generally, if there is a nested situation like [@ticket, comment], this would be a situation where if the @ticket wasn't assigned then there would likely be a lot more problems. However, it is still "good" practices to avoid the instance variables in the partials if possible. On top levels, i.e., a new action sets an instance variable and this renders new.html.erb, I would be a lot more likely to consume the instance variable within that new.html.erb.
With it rendered in the browser, inspect the elements to see if the jquery plugin is creating additional elements, you would then need to target these from within stimulus and can drill down to them from this.element.
