Emoji no longer display after upgrade to 148

Since updating Firefox from a previous version, the browser no longer displays any Unicode emoji characters. Where an emoji would normally be rendered (👁️), the browser instead displays empty space. Websites such as twitter and discord, which use their own artwork for emoji, are unaffected. This has negatively affected my browsing experience. For illustrative purposes, I will add a series of emoji and include a screenshot of how they are displayed: (😀🙁😡💀). Other characters still display correctly: (β❖♞䷲⎈𐘢𓀺இ). My computer otherwise displays emoji correctly. The issue persists after disabling extensions, and has persisted between computer restarts. I'm running Linux (NixOS) and Firefox version 148. I've tested on Chrome based browsers and they work fine. Tested on Firefox forks and they also don't display correctly. This is new since less than a week ago. Thanks for any help with this.