When calling ComputerListener.onOnline(Computer c) with the built-in node on startup, getDisplayName() returns "built-in". (did probe with ==Jenkins.get().getComputers()[0] and it was the built-in node)

When calling at any other time, getDisplayName() returns "master".

Recreatable using the console.

println Jenkins.instance.getComputers()[0].getDisplayName();

=> "master"

At least critical, may be blocking for some plugins if i am not the only one with this issue.