Complete lockout of web interface after changing theme ("We're sorry, but something went wrong on our end.")

[Flipp3rrr]

Steps to reproduce the problem

Steps to reproduce

1. Migrate from Mastodon 4.0.2 to hometown
2. Change (site) theme to 'Macaron' in Preferences > Appearance
3. Save changes
4. Cry

Expected behaviour

The theme should change

Actual behaviour

The web interface completely and irreversibly (?) breaks

Detailed description

All that remains of the web interface, on this specific user account, is the error We're sorry, but something went wrong on our end. The title, Hometown, is a link to example.com.

Specifications

• VPS on Ubuntu v20.04.05 LTX x86_64 (kernel v5.4.0-139-generic, 1GB RAM)

  • Mastodon v4.0.2+hometown-1.1.1
  • Ruby v3.0.4
  • Node.js v16.19.1

• Vivaldi 5.7.2921.53 (Chromium)

[Flipp3rrr]

I noticed a similar error message in bug #1295 relating to the browser's language settings. My instance worked at first, but I have my browser set to English with several other languages configured: en-GB, nl-NL, nl, en-US, en & zh-Hans (in this order).

[Flipp3rrr]

Quick addition; while the web interface is inaccessible, I am able to access my account through a 3rd-party client and interact like I normally would.

[Arduqq]

Seconding the bug under kernel 5.4.0-135-generic and Firefox 111.0..1.