On 06 July 2018 I caged an old dog on Xanadu and transported it to Independence. I released the dog on my deed on Independence, and then traveled back to Xanadu.
Today, 07 July 2018, when I tried to tame a deer I got the following message: "[13:23:56] You have a pet in a cage, remove it first, to tame this one."
I tried Pet > Clear orders with no result.
I tried the Un-Tame option under Manage > Animals (yes, the dog is listed on the Xanadu server) and got the message: "[13:25:25] This animal is caged, remove it first."
Looks like this may be a bug concerning transporting tamed animals across servers.