Editing footnote breaks formatting and yields error.

[bbernicker]

Whenever I click on a footnote to edit its contents, the formatting of the footnote changes to match the regular text. After that, whenever I click into the text of that footnote, I get the following error.

An error occurred

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TypeError: null is not an object (evaluating 'o[0]')
at undefined at line 2
ErrorId: chDtdsqKPaUZ4SvH9p5c
Uncaught exception
URL: [redacted]
UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.5 Safari/605.1.15