Folder names are not significant and can be updated.
The full file url is used by DW if you are working on a page that is not saved... it can't use the relative path since it doesn't know the location where the file will be eventually saved to.
It appears that because the code is in a comment, dreamweaver doesn't update the link properly as it would normally. This definitely could be considered a bug, but that is the description of the reason it occurs. We may be able to save the page earlier in the process to get around this problem.