I’d argue it’s a bug.
Subsequent rendering of $ expressions anywhere later in the document (many pages on) completely fails and it’s not clear what the cause of it is. Obsidian appears broken. It is not obvious what causes it and hard to fix for a user.
The tendency for the user is to find the issue with the non-rendering expression, which will not fix the problem no matter what you do. So it wastes (a bunch of) time. I spent a good 15 minutes figuring this out. Trying to fix the thing that looked broken.
At the very least, if the rendering of one expression fails, the subsequent expressions should still render. If that’s not possible, something red should show.