If you are requesting technical assistance with Twine, please specify:
Twine Version: 2.6.0
Story Format: SugarCube 2.36.1
If you have a passage with a name that starts with a space, but the link does not, Twine will just ignore the space. The link in the graphical display will work, and it will tell you there are no broken links.
But when you try to play the game (or test), the links fails.
I appreciate this will be rare, but it happened to me somehow. And I would consider it to be a bug. if the link is not going to work during play, it should not work in Twine itself. Or Twine should automatically trim names.