How do I bring this to the proper individuals' attention?
Someone went and edited the duplicate close banner, which normally shouldn't be able to happen. The problem in this case is that the question was closed before the current system was put in place and the the banner was handled differently back then.
I have edited it and re-closed it to fix the duplicate banner.
The way to go about reporting this is either via a custom moderator flag or by posting on meta as you have done.