Displays blank page in Safari Version 15.6.1 (15613.3.9.1.16, 15613)

A blank page is displayed when trying to load https://phanpy.social/#/

**To Reproduce**
Easy - visit https://phanpy.social/#/

**Expected behavior**
Expect feed to display something at least.

**Screenshots**

**Desktop

(please complete the following information):**
- OS: MacOS Catalina version 10.15.7 (19H2026)
- Browser Safari
- Version 15.6.1 (15613.3.9.1.16, 15613)

**Additional context**
Was working great until about a week ago. Still works fine in Firefox.
Get the following error in concole:
[Error] SyntaxError: Invalid regular expression: invalid group specifier name
RegExp (useTitle-e1a51531.js:36:103733)
Module Code (useTitle-e1a51531.js:36:103733)
evaluate
moduleEvaluation
moduleEvaluation
(anonymous function)
promiseReactionJob

Start by reproducing https://phanpy.social/#/ in Safari 15.6.1 and inspect the console error in useTitle-e1a51531.js, where the invalid regular-expression group specifier is reported. Trace that error to the corresponding application source and verify that the feed displays in Safari while continuing to work in Firefox.

Written by the indexing model from the issue text.