Unable to edit variables after 2021.3 Build 8275 upgrade: "Invariant failed"

Upgraded to 2021.3 Build 8275, and now I can’t edit variables.
Click on Variables in the project menu has no effect, and dev tools console catches multiple “Invariant failed” errors.
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I’ve sent an email to support, has anyone else seen this?

Hi Sean,
Thanks for reaching out.
We will process your ticket on the Support queue and close this one off.

Kind Regards,
Paraic

Here’s the bug if anyone else runs into this issue:

Hi Sean,

Thanks for updating this public thread with the bug report - great idea! Don’t hesitate to reach out with any questions or concerns in the future. :slight_smile:

Best regards,

Kenny