Ampersand in a link got replaced by the HTML entity

I'm on a server that runs the following versions:

• Backend version: 2.4.51-1957-gec41de22-emr-develop
• Frontend version: ea0887a1

I sent a DM with this link: https://www.webtoons.com/en/challenge/whats-up-beanie/bike-ride/viewer?title_no=295880&episode_no=394 It's rendered correctly, but the href attribute has ampersand replaced by the HTML entity: https://www.webtoons.com/en/challenge/whats-up-beanie/bike-ride/viewer?title_no=295880&episode_no=394 (note how & got replaced by &). This breaks the link.