I will look into this, It sounds like a bug, most likely an unhandled exception coming from the azure servicebus (but doesn't necessarily originate there)
I've created a github issue here: https://github.com/Particular/NServiceBus.Azure/issues/133
Are you able to reproduce the issue? And what has changed between the time where you saw it occasionally and where it happens often.
One thing you could do is to add an eventhandler for all exceptions occuring on the appdomain and log those as well, that should theorethically catch anything and if there is an innerexception to this callback exception you could catch it this way.
On the strict dependency of the packages. This is mostly done because nuget package manager does not apply binding redirects to the app.config of worker roles, which tripped up way to many users in the past (it often manifests itself as an infinitly rebooting worker role). So go ahead and override.