discourse/github breakage with custom slider settings: `svg.disabled` is on

Tested with Tor Browser 14.0.6 on Whonix

STR:

1. Remove/Disable NoScript
2. Put Tor Browser in "Safest" mode.
3. Explicitly make sure in about:config" that svg.disabledandjavascript.enabled` are both set to true.
4. Open and watch browser console
5. Open any Discourse forum homepage (that of Tor Project included) or some GitHub project (e.g. https://github.com/torvalds/linux)

Expected

Pages should load correctly.

Actual

Discourse:

Shows 5 animated dots and doesn't load further, thus making impossible to use the forums (e.g. to sign in etc).

GitHub:

Shows:

Error Looks like something went wrong!

For both Discourse and GitHub the console shows SVG-related error messages.

Further STR:

6. Set svg.disabled to false
7. Reload

Result

Everything works as expected.

Additional note

The issue with Discourse forums started appearing for me just recently. Speculation: perhaps due to update of Tor Browser, or all Discourse forums on the web (unlikely), or some combination of the two.