The two argument version of the <<link>> macro is expecting both of the arguments to be String values, and String values are meant you be quoted. So the above example should really be any of the following...
/* Using the same quotes for both of the String arguments. */
<<link 'Hello there' 'Link'>> <</link>>
<<link "Hello there" "Link">> <</link>>
/* Or even inconsistently using different quotes for the arguments! */
<<link 'Hello there' "Link">> <</link>>
<<link "Hello there" 'Link'>> <</link>>
warning: You shouldn't rely on the story format to guess that the Link value being passage to the macro is actually a String, because it might guess wrong which could result in an unexpected outcome.