Frequent crashing when clozing

[TEST987987123]

Describe the bug
Anki crashes rather frequently when clozing some text or changing the cloze number of some clozed text.
To Reproduce
Steps to reproduce the behavior:

1. Open the window to add a new card with
2. Write some text using a card type that allows for clozing
3. Cloze some text. If it hasn't crashed already, try changing or just selecting clozed texts' cloze numbers

Expected behavior
I expect Anki not to crash. It doesn't happen with SIAC disabled.

log
The last few lines before it crashed:

on_load_note > right_side_html()
JS info /_addons/1781298089/web/dist/siac.min.js:25 [SIAC] cacheFields(): .editing-area not found, retrying in 30ms.
JS info /_addons/1781298089/web/dist/siac.min.js:25 [SIAC] cacheFields(): .editing-area not found, retrying in 30ms.
JS info :14 [SIAC] right_side_html(): wrapping fields.
[SIAC] setup_ui_after_index_built()
1781298089/src/output.py:1075:night_mode() is deprecated: use theme_manager.night_mode
JS info /_addons/1781298089/web/dist/siac.min.js:29 [SIAC] Mathjax typeset fn not found.
JS error /_anki/legacyPageData?id=140678217922112:2 Uncaught SyntaxError: Unexpected token '<'
zsh: trace trap  anki

Environment (please complete the following information):

• OS: Arch Linux, 64 bit
• Anki version: 2.1.62 (77dd1dc1)

[n30s4m]

Terrible. Me too.