I've stumbled across a strange problem posting a specific block of text. [View all]

I've been trying to post a reply in GD. I've tried multiple times and only get a forbidden 403 response, and something about a danish/english translation.

Here is the text:



Here is the error message I get when I try spellcheck:


Here is the error message I get when I tried to post (both here and in GD)


I can reply to the post - with different words in the body
I can reply to my own reply - as long as I don't use the original text in the body
I pasted the message as plain text - same error
I retyped the entire message just in case I had some odd hidden character.
I deleted the embedded link
And I tried to paste it in the message here.

In case it matters, here is the link to the post: https://democraticunderground.com/?com=view_post&forum=1002&pid=20529492

But - both here and in GD - all the same result (despite successfully having successfully posted at least two other posts, as well as different text in response to the post). Any ideas?

ETA: by eliminating sentence by sentence, and then character by character, I've narrowed it down to this phrase that is the issue: