Fundamentally it seems that the update mechanism needs reworking so that it is more robust.That a third party tool can effectively 'pull the rug' from under Firefox seems like a fairly serious security hole to me. Just about other software app can ha...
I have been pursuing this issue via other avenues, and I have found that if you are on a computer managed by an RMM (ie a company computer with enforced update policies), the RMM can and will push through an update regardless of the policies you have...