Link to mail message not working

So when I drag and drop an email from Mail.app into OmniFocus, it automatically creates a link that works. I am making a plugin that will take that exact link and copy it to another task. However, now, the same text no longer works as a link. Please help!

Does the copying include the < and > at the beginning and end?

Yes, it does

That IS strange, when I do it links work in all apps.
Have you tried adding a line break? (Sometimes triggers a link?)
Just guessing, it seems very strange

Maybe you can share the script so we can test it?