When you right click on a baby trader llama with something in your off hand and nothing in your main hand you will try to get on it but cant and the baby trader llama will make the noise as if you were holding something in your main and trying to tame a adult llama. And it makes your off hand swing while right clicking
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Can confirm in 20w46a.
Can confirm in 21w03a.
Can confirm in 1.16.5 and 21w08b.
Video attached.
Can confirm in 21w15a.
Can confirm in 21w16a.

This also happens with baby horses and probably baby mules and donkeys.
Can confirm in 1.17.
Can confirm in 1.17.1.
Can confirm in 1.18.1.
Can confirm in 1.18.2.
Can confirm in 1.19.2.