Upfront UI is displaying strange code instead of the actual content

I first had an issue with Upfront not working on my sub-domain multisite installation, so I switched to a new domain and now the UI is loading with a bunch of {{ content }}/etc instead of the actual content. Before the Upfront UI wouldn't load at all on the other sites, now it loads but it's showing those bracket codes.

The first site that I created does work correctly, but the other two are not.
I am also getting these errors in the console, but I'm not sure if they're related:
SyntaxError: expected expression, got '<'
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ucontact.html:1
TypeError: t is undefined
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main-1.9.4.js:88:566