Harper Not Working on Letterboxd

**Describe the bug**
Looks as if Harper has stopped working properly on Letterboxd, leaving me to constantly go back and forth between editing directly on the Harper website. Most other websites are unaffected as of now.

**Steps to reproduce**

1. Open Letterboxd
2. Log any film and try to write a review
3. Deliberately write any spelling mistake

**Expected behavior**
The spelling/grammar mistakes should be underlined.

Usually, if I'm writing a review on Letterboxd, I'd expect Harper to immediately highlight a possible mistake (or in the case of this screenshot, an unfamiliar surname), but the underlines are not appearing whatsoever. I've tried uninstalling and reinstalling Harper, only for the glitch to remain there. Is there a possible fix for this?

**Screenshots**

**Platform**
Must note I'm using Firefox right now, but I've also noticed that this is happening on any other Chromium browser that I'm using too.

Start by reproducing the issue on a Letterboxd review in Firefox and a Chromium browser, using an intentional spelling mistake as described. Compare the editor behavior with Harper's website; the work is done when spelling or grammar mistakes are underlined on Letterboxd in the affected browsers.

Written by the indexing model from the issue text.