TankAuth uses PHPass for password hashing with portable mode set to FALSE by default that lets PHPass uses bcript instead since portable hashes does not store salt in its hash.
But, if we want to move the database to different server, we need to set it to TRUE even before adding records to table to avoid regenerating the passwords later. Evidently, keeping portable hashes TRUE makes the encrypted passwords is quite unsafe
Is there any better solution using tank auth to bcrypt the password hash yet painless database migration across servers?
I think you will need to bite the bullet and turn on portable mode. It is unfortunate, but as stated in the question provided by @CyberJunkie, it's necessary.