WebRTC fails tests on Firefox 78.10.0esr (64-bit)

Having to participate in many online events since the COVID crisis started, I've come to notice that few of the online clients work properly on the current Firefox ESR found in Debian. A quick visit at WebRTC Test confirmed that none of the tests in the Network and Connectivity section pass. Meanwhile, a Windows 10 laptop running Edge via the same network works just fine, so I have to assume that either a Firefox or Debian packaging issue is to blame, but I wouldn't know where to start. Any help? Thanks!