To receive an error saying this domain can't be transferred:

Received an error saying the domain is already mapped to a WordPress site:

This causes confusion as the user isn't informed that the domain isn't eligible for transfers.
This came up in 4842940-hc when the user was trying to transfer their .co.uk domain in. The message left them and me confused since the error was a false report (a mapped domain can be transferred). It wasn't until I realized the extension couldn't be transferred that we could connect the dots.
A crucial bit of information is that this only occurs if the domain the user is trying to transfer in is _already_ mapped on WPCOM.
Otherwise, the correct notice is shown:

Happened with another user with a _.us_ domain.
Context / Source
5523275-hc
Happened with another user with a .ca domain.
Context / Source
11263679-hc
Another report, for an .se domain. This confused the user, and added a support interaction that wasn't required if the messaging was clear.
Another one, a .co.za domain this time.
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