Label crate that can't be erased

[Glim]

Danten has a crate that cannot be erased.

<left hand> a wooden crate labelled: unknown - inv (perfect)

I have tried it with an empty inventory and nothing else was held in his hand but the crate.

If I hold a quill and try to label it it reports:
You should first erase the crate's label.

[Rordan]

Weird!

Just to confirm, if you hold the crate and type 'erase' it doesn't do anything? Doesn't clear the label at all?

[Glim]

It gives you the echo that the label is erased.

But the label is not erased.