When did this change?
When FEU took over US operations.
And why would they not allow a paying customer to have one mount moved from one character on the server to another, which is also on the same account?
There was never a mount transfer. What there was a process when GMs would contact player, verify that player has the mount, ask player to delete the mount, verify that this was done and then send a new mount to new account. Very manual and cumbersome process.
If I knew about this change I would have just bought a new mount on the character I want the lion moved to rather than have two mounts on one character...
Sorry... Caveat Emptor. I take it, shared mount bag is not working. I thought you were supposed to be able to do that with toons on same account.