It's not a bug.
In the v1.28 update, Eric Gurt introduced a version of the Star Defender in the old PB:FTTP style. You can see that both character models exist in the Advanced Level Editor.
Chances are you were playing a map that used the PB:FTTP model of the Star Defender.
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Nevermind!
Disregard what I said above. It seems that the Star Defender skin now defaults to the PB:FTTP version. It's not a bug though, so don't worry.