Issues with hand-feeding for imprinting wyverns

[Wolfguarde]

I'm running into a persistent issue with any wyverns I attempt to feed on the server I play on. Imprinting works as it should in most instances, except for hand-feeding them milk. There's no prompt, force-feeding them doesn't work, simply putting it in their inventory doesn't work, and unclaiming/reclaiming them doesn't work. While not being able to imprint them isn't the end of the world, it's something I'd like to fix if possible. Am I missing the obvious, or is this a common issue? What kind of solutions have people found to work for it in the past?

[Guzz]

Put milk on slot 0

[Wolfguarde]

You, sir, are a gentleman and a saint, and I'm an idiot. Thank you!