"Native audio capture failed to start" error when screensharing librewolf on linux

Reproduction steps

install and open librewolf (i use the appimage, not sure if that matters)
join a call and attempt to screenshare a librewolf window with audio

i tried with several different apps and it only seems to happen with librewolf. it works fine with firefox

Expected behaviour

screenshare starts successfully

Actual behaviour

pasted-image-1.png (SEO: "Screen share audio couldn't start" "Turn off audio sharing for this source or try again in a moment.") i started fluxer from the terminal and saw this error in the output:

23:23:52.492 › [NativeAudio] Native audio capture failed to start {
  captureId: '24cc8cce-fc96-4e82-b332-475095e352b8',
  error: 'Error: include exceeds pattern cap\n' +
    '    at ProcessLoopback.start (/tmp/.mount_fluxerfOkIng/resources/app.asar/node_modules/@fluxer/linux-audio-capture/index.js:263:21)\n' +
    '    at xk (file:///tmp/.mount_fluxerfOkIng/resources/app.asar/dist/main/MainApp.js:251:44093)\n' +
    '    at async Session.<anonymous> (node:electron/js2c/browser_init:1:119032)'
}
Error occurred in handler for 'native-audio:start': Error: include exceeds pattern cap
    at ProcessLoopback.start (/tmp/.mount_fluxerfOkIng/resources/app.asar/node_modules/@fluxer/linux-audio-capture/index.js:263:21)
    at xk (file:///tmp/.mount_fluxerfOkIng/resources/app.asar/dist/main/MainApp.js:251:44093)
    at async Session.<anonymous> (node:electron/js2c/browser_init:1:119032) {
  code: 'InvalidArg'
}

Build information

Stable Desktop 2026.1026.24218, Web 2026.1028.174822, Linux 6.8.0-147-generic (x64), Electron 44.9.1, Chrome 152.0.7977.167, Node 24.22.0, Locale en-US

Platform

Linux