Was hdragsil corrupted by some mod (Quest Pack or something)? Because the vanilla version is fine after running the code I posted, even without validity/reindexing.
Do you have a vanilla example of a 'zeroed out cre'? I'll admit, I'm not quite sure why zeroing out some offsets is a good idea (I think it was a Taimon utility that did this - I'm assuming he had a good reason for it).
QP overwrites with a cre with a zeroed offset.
Taimon's code fixed zeroed offsets, if I'm not mistaken.
Zeroing offsets is a stupid thing to do and is hopefully not done on purpose.