Thanks everyone, that clears up a lot. The part I missed was the vertical bar, it was tricky to debug since putting any string out in any way to display ends up interpreting the vertical bars. Indeed everything works now and Lua is not behaving inconsistently as I first thought.
Is there a raw dump which doesn't interpret all the strings (I may write a helper function for that now that I know what is going on)
Also out of curiosity what are all the other numbers in the link?
The links I see seem to be of the form:
|H<color>:<type?>:<id?>:<n1>:..:<n19>|h<linkname>|h
The color is clear. What are the possibilites for type (I am assuming it is the type of thing getting linked... I usually see "item" there). Is the next number the ID for that type (item ID for instance)? Anyone know what all the other numbers are (I generally see 19 more, but maybe that is dependent on what is getting linked?)