No, it should be an official thing supported by Jolla if you don't want it to fail miserably. Relying on goodwill of some Jolla devs to follow that bugtracker won't really produce a good result. I.e. if Jolla has some concerns which prevent them from making a public bugtracker, they need to be addressed first.

Sailfish should be supposedly open (even though it's not yet - many packages are closed for now). So open bugtracker fully makes sense from community perspective.

https://sailfishos.org/about-license.html