"Facebook Messenger" web page not available

Hi, thanks for the app. It's a great idea.
I'm running Calyxos (Android 15) on a pixel 8 pro. Facebook loads ok but if I tap the Messenger icon I get the "Web page not available" message.

Followed by:
The web page at fb-messenger://threads?vcuid=100007866033591&is_msite_sso_eligible=1&entry_point=jewel&browser_name=Chrome&mb=Abgxq1ryEZiUu39xEZO8FOSWZ4CuBanzOUYbJmD8WX8323Feto3r0PcPzD4dVpz9cWFVeaIfHXFSTHmkxKbmr08pSTjLnoGl6YFJMjbUuDk6dShrBznQ5CtxdXeTVO18Lw9cRgyaUuqyszSl90rH6BnDRnQoyx6N25wuyGwPnlZMm4jCXR1Cwb-o1DZ8y1bz6kp7E20udEvtjmJkbNXGS40zzhc&src=mtouch_diode
could not be loaded because:

net::ERR_UNKNOWN_URL_SCHEME

Also I'm getting the "Open app" dialogue on the bottom of the main screen. Is this normal behavior?

Thanks.