Firefox Snap won't open links to WhatsApp API


I’ve encountered a problem using the snap version of Firefox: when trying to open a link to WhtasApp API (…), instead of handling it by itself the browser opens a popup requesting to choose an application:

System Handler fails (as there is no app that could interpret the link) and I haven’t found a way to tell Firefox “use Firefox”.

I opened a bug on Launchpad:

Have someone found themselves in the same situation?

Seems like the “Open in Firefox” option is missing for these links: